Preheat the oven to 425F.
Over medium heat, sauté bell pepper, onion, jalapeño, and garlic until soft, about 4 minutes. Remove and set aside.
In the same pan, brown the ground beef until fully cooked, about 6 minutes, breaking up the beef with a spoon or spatula. Drain any fat left in the pan and add chili powder, cumin, paprika, salt and pepper.
On a sheet pan, overlap 6 tortillas around the edge to cover the entire pan. Place one tortilla in the center to ensure complete coverage. Top tortillas with ground beef, vegetables, cheese, and scallions.
Place the remaining tortilla in the center of the sheet pan and fold all the others towards the center. Place a second sheet pan on top and gently press down. Bake for 18-20 minutes, remove the top sheet pan, and bake for another 12-15 minutes or until the tortillas are golden and crispy.
Slice the quesadilla and serve with sour cream and salsa.