1. Prepare the Buffalo Chicken Filling: Cook and shred chicken (approximately 2 cups). In a medium bowl, combine shredded chicken, Frank’s RedHot, melted butter, optional ranch dressing, garlic powder, onion powder, and black pepper. Stir well until chicken is thoroughly coated. Taste and adjust seasoning/hot sauce. Set aside (can be made a day in advance).

2. Assemble the Sandwiches: Lay out 8 bread slices. Lightly spread one side of each slice with softened butter (this is the outside). Flip 4 bread slices over (buttered-side down) for the bottom halves. On these unbuttered sides, layer cheese: one slice sharp cheddar, then one slice Monterey Jack. Evenly divide the Buffalo chicken mixture among the 4 cheese-topped slices, spreading gently. If using, sprinkle blue cheese crumbles over chicken. Top chicken with another slice of sharp cheddar on each sandwich. Place the remaining 4 buttered-side-up bread slices on top.

3. Grill the Sandwiches: Heat a large skillet, griddle, or pan over medium-low heat. Place 1 or 2 assembled sandwiches onto the hot skillet (don’t overcrowd). Grill for 4-6 minutes on the first side until golden brown and crispy, pressing gently with a spatula. Carefully flip and grill the other side for another 4-6 minutes until golden brown and crispy, and cheese is fully melted. Reduce heat if browning too quickly. Remove and repeat with remaining sandwiches.

4. Serve: Let sandwiches rest for 1-2 minutes before slicing diagonally. Serve immediately while hot and melty, optionally with ranch or blue cheese dressing for dipping, and celery/carrot sticks. Enjoy!