Prepare the Buffalo Chicken: In a small bowl, whisk together the hot sauce, melted butter, and garlic powder to create the buffalo sauce. In a separate bowl, toss the shredded chicken with the sauce until it's evenly coated.

Assemble the Sandwich: Lay out the two slices of bread. On one slice, place half of the Monterey Jack (or provolone) cheese. Top the cheese with the sauced buffalo chicken, then sprinkle the crumbled blue cheese (if using) over the chicken. Finish with the remaining shredded Monterey Jack cheese on top of the chicken.

Butter and Grill: Place the other slice of bread on top of the sandwich. Generously spread the softened butter on the outside of both slices.

Cook the Sandwich: Heat a non-stick skillet or a griddle over medium-low heat. Place the sandwich in the pan and cook for 4-6 minutes, or until the bottom is golden brown and the cheese is beginning to melt.

Flip and Finish: Carefully flip the sandwich and cook for another 4-6 minutes, or until the second side is golden and the cheese is completely melted and gooey.

Serve: Remove the buffalo chicken grilled cheese from the skillet. Slice it in half and serve immediately with a side of ranch or blue cheese dressing for dipping.