Caramelized red onions add a rich, sweet dimension to these mushroom, spinach, and pepper Jack-stuffed tortillas. The quesadillas can be assembled up to three hours ahead of time and baked just before you're ready to serve them.
In a hurry? These satisfying quesadillas take just 15 minutes to make. We like them with black beans, but pinto beans work well too. If you like a little heat, be sure to use pepper Jack cheese in the filling. Serve with: A little sour cream and a mixed green salad.