Like sandwiches, tortillas vary enormously - there is no ONE quesidilla!
All we need are TORTILLAS - corn, flour, jalapeno, spinach, sun dried etc. and FILLINGS:
caramelized or fresh uncooked onions
shredded greens, like spinach, lettuce, cilantro, parsley
cheeses like shredded cheddar, jack, gorgonzola, feta, etc.
olives, chilis, sliced peppers and more
beans - black, white, red kidney, chickpeas, hummus
Warm tortillas in a skillet
Fill them immediately by folding them or using two tortillas, make a sandwich
Either serve immediately or warm again in the skillet and then serve.