Rinse chicken breasts and pat dry with paper towels. Butterfly the breasts and cut in half to make thinner cutlets.
Season chicken with garlic salt and black pepper. Cook chicken however you like. We cooked ours on the grill.
Slice chicken into thin 2-inch long strips. Set aside.
Cook bell pepper and onion. We grilled ours by cutting the bell pepper in half and removing the pith and seeds and slicing the onion into thick rings. Once cooked, chop the vegetables.
Brush one side of tortilla with butter. Place tortilla, butter side down, on a wire rack. Add a handful of cheese to one side of the tortilla, enough to cover.
Add some chicken, bell pepper, red onion, and green onion over the cheese.
Cover chicken and vegetables with more cheese.
Fold tortilla over to encase the fillings.
Butter a large heavy bottomed skillet, enough the coat the bottom and sides, and heat over medium.
When skillet is hot, add folded tortilla to the skillet and cook for 3-5 minutes. You want the cheese to begin melting and the tortilla to brown.
Flip the quesadilla over and cook an additional 2-4 minutes until nicely browned and cheese is melted. If you need to flip more than once, that’s okay too!
If you have a flat top grill or skillet it is easier to use than a regular skillet.
Using medium heat is best so that you don’t cook the outside of the tortilla before the cheese has a chance to melt.
Cheese should be at room temperature so that is not too cold to melt.
I would always suggest using a block of freshly shredded cheese over store-bought. Store-bought shredded cheese contains anti-caking agents which prevent them from melting well and can sometimes cause the cheese to have a grainy texture.