Watch the butter! Butter burns very quickly so keep an eye on it. Add your tortillas when it’s just melted. Leftover quesadillas can be stored in an airtight container for up to 5 days in the fridge. Gently reheat in a frying pan over medium-low heat until warmed through. To freeze, tightly wrap in foil or plastic wrap and place in a freezer-safe zip-top bag. Freeze for up to 3 months. Thaw overnight in the fridge and reheat when ready to eat.