This is simple and good. My mom first made it for me.
Potato and Cheese Quesadillas
cooked potato (mashed, baked, whatever)
corn (or flour) tortillas
butter or oil
Melt butter in pan. Place potato and cheese on one tortilla. Place in pan on top of heated butter. Put another tortilla on top. Fry until crispy. Add butter and flip. Fry until crispy.