1. Heat a large skillet over medium heat and cook the ground beef until browned, breaking it into small crumbles as it cooks. Drain excess grease if needed.

2. Add the chopped onion to the skillet and cook until softened, then stir in the minced garlic and cook for 30 seconds.

3. Sprinkle in the taco seasoning, salt, and black pepper. Add the water and stir well, then simmer for 2 to 3 minutes until the beef mixture is thick and well coated.

4. In a small bowl, combine the cheddar cheese and Monterey Jack cheese.

5. Lay out the tortillas and sprinkle cheese over one half of each tortilla. Spoon the beef mixture over the cheese, then top with a little more cheese. Fold each tortilla in half.

6. Melt a little butter in a clean skillet over medium heat. Cook each quesadilla for 2 to 3 minutes per side until golden brown and crisp and the cheese is melted.

7. Transfer to a cutting board, rest for 1 minute, then slice into wedges and serve warm.