Add ground beef, garlic and onion in a medium pan over medium heat. Cook till beef is browned and onions are softened. Add in water, taco seasoning, corn and chili. Heat till liquid has evaporated. Set aside.
Layer the mozzarella and beef mixture in between each pair of tortillas evenly.
In a large frying pan heat butter over medium heat. Add in quesadillas and cook till cheese has melted.