Cheesy Zucchini and Spinach Gratin

After a long week, nothing sounds better than a comforting, home-cooked meal that’s both satisfying and relatively easy to prepare. This Cheesy Zucchini and Spinach Gratin has become a regular star in our dinner rotation for just that reason! The first time I made it, I was looking for a way to get more vegetables into our meals without sacrificing flavor – and boy, did this recipe deliver. The creamy, cheesy sauce blankets tender zucchini and spinach, creating a dish that’s both healthy and utterly indulgent. Even my picky eaters, who usually eye anything green with suspicion, devoured this gratin. The golden, bubbly top layer of cheese is simply irresistible, and the subtle nutmeg and garlic notes add a layer of sophistication that elevates it beyond your average vegetable side dish. It’s become a go-to for weeknight dinners, potlucks, and even special occasions when I want a crowd-pleasing vegetarian option. Honestly, if you’re looking for a recipe that’s both delicious and surprisingly simple, this Cheesy Zucchini and Spinach Gratin is a must-try.

Ingredients

• Zucchini: 2 lbs, medium-sized, sliced into ¼ inch thick rounds. Zucchini forms the hearty base of our gratin, offering a mild, slightly sweet flavor and tender texture when cooked. Look for firm, blemish-free zucchini for the best results.
• Fresh Spinach: 10 oz, roughly chopped. Spinach adds a vibrant green color and a boost of nutrients. Fresh spinach wilts beautifully into the creamy sauce, providing a subtle earthy counterpoint to the richness of the cheese.
• Heavy Cream: 1 ½ cups. Heavy cream is the foundation of our luscious and decadent cheese sauce. Its high fat content ensures a rich, velvety texture that coats the vegetables perfectly.
• Milk: ½ cup. Milk thins out the heavy cream slightly, preventing the sauce from becoming too heavy while still maintaining its creamy consistency. Whole milk is recommended for the best flavor and texture.
• Gruyere Cheese: 6 oz, grated. Gruyere is a key player in this cheesy gratin, known for its nutty, slightly salty flavor and excellent melting properties. It creates a beautifully browned and bubbly top layer and adds depth to the overall taste.
• Parmesan Cheese: 2 oz, grated. Parmesan cheese adds a sharp, savory, and salty dimension to the gratin. Its strong flavor complements the Gruyere and enhances the overall cheesy profile.
• Garlic: 2 cloves, minced. Garlic provides an aromatic base note that elevates the savory flavors of the gratin. Minced garlic infuses the cream sauce with its pungent and slightly sweet essence.
• Nutmeg: ¼ teaspoon, freshly grated. Freshly grated nutmeg introduces a warm, slightly sweet, and aromatic spice that complements the cheese and vegetables beautifully. Its subtle flavor enhances the overall complexity of the dish.
• Salt: 1 teaspoon, or to taste. Salt is essential for seasoning and balancing the flavors of all the ingredients. It enhances the sweetness of the zucchini, the earthiness of the spinach, and the richness of the cheese sauce.
• Black Pepper: ½ teaspoon, freshly ground, or to taste. Freshly ground black pepper adds a subtle spice and depth of flavor. It complements the nutmeg and garlic, creating a well-rounded savory profile.
• Olive Oil: 2 tablespoons. Olive oil is used for sautéing the garlic and zucchini, adding a touch of richness and preventing sticking. Choose a good quality olive oil for the best flavor.
• Breadcrumbs (Optional): ¼ cup, panko or regular. Breadcrumbs provide a delightful textural contrast to the creamy gratin. Sprinkling them on top before baking creates a crispy, golden crust. Panko breadcrumbs offer extra crunch.

Instructions

1. Preheat the Oven and Prepare Baking Dish: Preheat your oven to 375°F (190°C). While the oven is preheating, lightly grease a 9×13 inch baking dish with butter or cooking spray. This will prevent the gratin from sticking to the bottom and make cleanup easier. Using a baking dish of this size ensures even cooking and a good ratio of vegetables to sauce.
2. Sauté the Garlic and Zucchini: Heat olive oil in a large skillet over medium heat. Once the oil is shimmering and heated through, add the minced garlic and sauté for about 30 seconds, until fragrant but not browned. Be careful not to burn the garlic, as this will impart a bitter taste. The fragrant garlic will infuse the oil, creating a flavorful base for the zucchini.
3. Add Zucchini and Cook: Add the sliced zucchini to the skillet and cook for 5-7 minutes, stirring occasionally, until it is slightly softened but still holds its shape. You don’t want to fully cook the zucchini at this stage, as it will continue to cook in the oven. Sautéing it first helps to remove some of the excess moisture and ensures it has a pleasant texture in the final dish.
4. Wilt the Spinach: Add the chopped fresh spinach to the skillet with the zucchini. Cook for another 2-3 minutes, stirring until the spinach is completely wilted and reduced in volume. Fresh spinach wilts down significantly, so don’t be alarmed by the initial volume. Wilting the spinach beforehand ensures it’s tender and evenly distributed throughout the gratin.
5. Season the Vegetables: Season the zucchini and spinach mixture with salt, pepper, and freshly grated nutmeg. Stir well to ensure the seasonings are evenly distributed and coat all the vegetables. Taste and adjust seasonings as needed. Nutmeg is a subtle but crucial spice that enhances the overall flavor profile.
6. Prepare the Cream Sauce: In a separate medium saucepan, combine the heavy cream and milk. Heat over medium heat until it just begins to simmer. Do not boil. Heating the cream and milk together creates a smooth and cohesive sauce base. Simmering helps to slightly thicken the mixture.
7. Add Cheese to the Sauce: Reduce the heat to low. Gradually add the grated Gruyere and Parmesan cheese to the cream mixture, stirring constantly until the cheese is completely melted and the sauce is smooth and creamy. Stirring constantly is important to prevent the cheese from clumping and to ensure a velvety smooth sauce. The combination of Gruyere and Parmesan provides a complex and rich cheesy flavor.
8. Combine Vegetables and Sauce: Pour the creamy cheese sauce over the zucchini and spinach mixture in the skillet. Gently stir to combine everything evenly, ensuring the vegetables are well coated in the sauce. This step brings all the components together, creating the heart of the gratin.
9. Transfer to Baking Dish and Top with Cheese: Pour the mixture into the prepared baking dish, spreading it out evenly. Sprinkle the remaining grated Gruyere and Parmesan cheese evenly over the top of the gratin. This extra layer of cheese will create a beautiful golden brown and bubbly crust during baking.
10. Add Breadcrumbs (Optional): If using breadcrumbs, sprinkle them evenly over the cheese topping. Breadcrumbs add a delightful crispy texture to the top of the gratin.
11. Bake the Gratin: Bake in the preheated oven for 20-25 minutes, or until the gratin is bubbly, golden brown on top, and heated through. The baking time may vary slightly depending on your oven. The gratin is ready when the cheese is melted, bubbly, and starting to brown, and the internal temperature is heated through.
12. Let Rest and Serve: Remove the gratin from the oven and let it rest for 5-10 minutes before serving. This allows the gratin to set slightly and makes it easier to serve. Resting also helps to prevent it from being too runny. Serve hot and enjoy!

Nutrition Facts

(Per Serving, approximately 6 servings per recipe)

• Calories: 420 kcal
• Fat: 35g

Note: Nutritional values are estimates and can vary based on specific ingredients and portion sizes.

Preparation Time

• Prep Time: 20 minutes (This includes washing and slicing vegetables, mincing garlic, grating cheese, and preparing the sauce.) The preparation is relatively straightforward and doesn’t require any complicated techniques, making it a great option for a weeknight meal.
• Cook Time: 30 minutes (This includes sautéing the vegetables and baking the gratin in the oven.) The majority of the cooking time is hands-off in the oven, allowing you to focus on other tasks while the gratin bakes to golden perfection.
• Total Time: 50 minutes (From start to finish, you can have this delicious and comforting gratin on the table in under an hour!) This makes it a wonderfully efficient and satisfying meal option for busy individuals and families.

How to Serve

This Cheesy Zucchini and Spinach Gratin is incredibly versatile and can be served in numerous ways, making it a fantastic addition to any meal. Here are some delightful serving suggestions:

• As a Side Dish:
  • Alongside Grilled or Roasted Meats: Pair it with grilled chicken, steak, pork chops, or roasted lamb for a balanced and flavorful meal. The creamy gratin complements the richness of the meat beautifully.
  • With Fish or Seafood: Serve it as a side to baked salmon, pan-seared cod, or grilled shrimp. The delicate flavors of fish and seafood are enhanced by the cheesy vegetable gratin.
  • Vegetarian Main Course Accompaniment: Pair it with a hearty salad, lentil soup, or crusty bread for a complete and satisfying vegetarian meal. The gratin provides substance and richness to vegetarian plates.
• As a Vegetarian Main Course:
  • With a Green Salad: Serve a generous portion of the gratin with a fresh green salad dressed with a light vinaigrette. The salad adds freshness and acidity to balance the richness of the gratin.
  • With Crusty Bread: Enjoy it with slices of warm, crusty bread for dipping into the creamy sauce. Sourdough, baguette, or ciabatta are excellent choices for soaking up all the deliciousness.
  • With a Poached Egg on Top: For an extra touch of richness and protein, top each serving with a perfectly poached egg. The runny yolk adds another layer of creamy indulgence.
• For Special Occasions:
  • Holiday Side Dish: This gratin makes an elegant and crowd-pleasing side dish for Thanksgiving, Christmas, or Easter dinner. It’s a welcome vegetarian option among traditional holiday fare.
  • Potlucks and Gatherings: It travels well and is delicious served warm or at room temperature, making it perfect for potlucks, picnics, and family gatherings.
  • Brunch or Lunch: Serve smaller portions as part of a brunch spread or a light lunch. It pairs well with other brunch favorites like quiches, frittatas, and fruit salads.
• Serving Tips:
  • Garnish: Garnish with fresh herbs like chopped parsley, chives, or thyme for added freshness and visual appeal.
  • Temperature: Serve warm for the best texture and flavor. It can also be enjoyed at room temperature, though the cheese may become slightly less melty.
  • Portion Size: Adjust portion sizes based on whether you’re serving it as a side or a main course. For a side dish, smaller portions are appropriate; for a main course, serve more generously.

Additional Tips for the Best Cheesy Zucchini and Spinach Gratin

To ensure your Cheesy Zucchini and Spinach Gratin turns out perfectly every time, here are eight helpful tips and tricks:

1. Don’t Overcook the Zucchini: When sautéing the zucchini, cook it just until it begins to soften but still retains some firmness. Overcooked zucchini can become mushy in the gratin. You want it to have a pleasant bite and texture even after baking.
2. Squeeze Excess Moisture from Spinach: After wilting the spinach, gently squeeze out any excess moisture. Too much liquid from the spinach can make the gratin watery. This step ensures a creamier and more concentrated flavor.
3. Use Freshly Grated Cheese: Always use freshly grated cheese, especially Gruyere and Parmesan. Pre-shredded cheese often contains cellulose to prevent clumping, which can hinder melting and result in a less smooth sauce. Freshly grated cheese melts much better and has a superior flavor.
4. Fresh Nutmeg is Key: While ground nutmeg can be used in a pinch, freshly grated nutmeg provides a much brighter and more aromatic flavor. The difference is significant, and freshly grated nutmeg elevates the overall taste of the gratin.
5. Adjust Cheese Ratio to Your Preference: Feel free to adjust the ratio of Gruyere and Parmesan cheese to suit your taste. For a milder flavor, use more Gruyere; for a sharper flavor, increase the Parmesan. You can also experiment with other cheeses like Fontina, Mozzarella, or cheddar for different flavor profiles.
6. Add a Pinch of Dijon Mustard to the Sauce: For an extra layer of flavor complexity in the cream sauce, whisk in a teaspoon of Dijon mustard. Dijon mustard adds a subtle tang and depth that complements the cheese and vegetables without being overpowering.
7. Customize with Other Vegetables: Feel free to incorporate other vegetables into your gratin. Sliced mushrooms, bell peppers, onions, or cherry tomatoes would all be delicious additions. Just be sure to sauté them along with the zucchini and spinach. Roasted vegetables like butternut squash or sweet potatoes can also be added for a heartier fall version.
8. Make it Ahead of Time: You can assemble the gratin ahead of time and store it, unbaked, in the refrigerator for up to 24 hours. When ready to bake, simply add about 10-15 minutes to the baking time to ensure it’s heated through. This makes it a great option for entertaining or meal prepping.

Frequently Asked Questions (FAQ)

Q1: Can I use frozen spinach instead of fresh?
A1: Yes, you can use frozen spinach. Thaw the frozen spinach completely and squeeze out as much excess moisture as possible before adding it to the skillet. About 10 ounces of frozen spinach, thawed and squeezed, is a good substitute for fresh spinach in this recipe. Keep in mind that fresh spinach has a slightly milder flavor and better texture in gratins.

Q2: Can I make this gratin dairy-free or vegan?
A2: Making this gratin completely dairy-free or vegan will significantly alter the recipe, but you can try some substitutions. For a dairy-free version, you can use plant-based heavy cream alternatives (like cashew or oat cream) and nutritional yeast to mimic some of the cheesy flavor. Vegan cheese shreds can also be used, though they may not melt as smoothly as dairy cheese. The flavor and texture will differ from the original recipe.

Q3: Can I add protein to this gratin to make it a more complete meal?
A3: Absolutely! You can add protein to make it a heartier main course. Cooked chicken, sausage, or bacon can be added to the vegetable mixture before baking. For a vegetarian protein boost, consider adding cooked lentils, chickpeas, or white beans. Tofu or tempeh, sautéed and seasoned, can also be incorporated for a vegan protein option.

Q4: How long does leftover gratin last in the refrigerator?
A4: Leftover Cheesy Zucchini and Spinach Gratin can be stored in an airtight container in the refrigerator for up to 3-4 days. Ensure it cools completely before refrigerating. Reheat thoroughly before serving.

Q5: What’s the best way to reheat leftover gratin?
A5: The best way to reheat gratin is in the oven. Preheat your oven to 350°F (175°C) and bake the gratin, covered with foil, for about 15-20 minutes, or until heated through. You can also reheat it in the microwave in shorter intervals, but the texture may become slightly softer. For crispier results, remove the foil for the last few minutes of reheating in the oven.

Q6: Can I freeze this gratin?
A6: Freezing gratin is not highly recommended as the creamy sauce and vegetables can change texture upon thawing and reheating, potentially becoming grainy or watery. However, if you must freeze it, allow it to cool completely, then wrap it tightly in plastic wrap and then foil. Freeze for up to 1-2 months. Thaw completely in the refrigerator overnight before reheating in the oven. Be aware that the texture may not be as perfect as freshly made gratin.

Q7: I don’t have Gruyere cheese. What’s a good substitute?
A7: If you don’t have Gruyere, good substitutes include Swiss cheese, Fontina, or Jarlsberg. These cheeses have similar melting properties and nutty, slightly sweet flavor profiles that will work well in this gratin. You can also use a combination of mozzarella and Parmesan for a milder, more readily available option.

Q8: Can I use breadcrumbs for the topping if I don’t have panko?
A8: Yes, you can use regular breadcrumbs if you don’t have panko. Panko breadcrumbs provide a coarser, crispier texture, but regular breadcrumbs will still add a nice textural contrast to the creamy gratin. You can also use crushed crackers or even toasted almond slices for a different topping variation.

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