Cheeseburger Quesadilla on a Sheet Pan

Heat the oil in a large frying pan and lightly fry some of the onion.
Add the garlic and stir, then add the beef and fry until browned on all sides.
Season with salt and pepper and toss with ketchup.
Place parchment paper on a baking sheet and grease it with melted butter, arrange the tortillas and place the cheese slices on top.
Add the cooked beef, cover with tortillas, and grease them again with butter. Sprinkle with a few sesame seeds.
Bake at 220C/440F for 15 min