In a 12″ frying pan, saute onions in olive oil until tender. Remove from pan.

Place 1 tortilla in same pan over medium heat, top one side with cooked onions, chopped peppers and cheese. Fold tortilla in half to cover filling. Heat tortilla until cheese starts to melt, then flip and heat on other side for another minute or two.

Repeat with remaining tortillas and filling. You can keep cooked quesadillas in oven at low temperature to keep warm while cooking the rest.