Preheat the air fryer. Set it to 375°F (190°C) and let it warm up for a few minutes. A hot basket helps the tortillas crisp quickly.

Cook the beef. In a large skillet over medium-high heat, brown the ground beef, breaking it up as it cooks. Season with salt and pepper. Drain excess fat if needed.

Add aromatics and spices. Stir in finely chopped onion and diced bell pepper. Cook until softened, about 3–4 minutes. Add minced garlic (or garlic powder) and cook 30 seconds.

Season the filling. Sprinkle in taco seasoning and stir to coat. Add a spoonful of tomato paste or a few tablespoons of salsa to bring it together and keep the filling juicy. Simmer 1–2 minutes, then remove from heat.

Assemble the quesadillas. Lay a tortilla on a cutting board. Sprinkle a thin layer of cheese over half the tortilla, add a few spoonfuls of beef mixture, then top with more cheese. Fold the tortilla over into a half-moon. Repeat with remaining tortillas.

Lightly oil for crispness. Brush the outside of each folded tortilla with a bit of oil. This helps it turn golden and keeps it from drying out.

Air fry in batches. Place quesadillas in a single layer in the basket. Don’t overcrowd. Air fry for 5–7 minutes, flipping halfway, until the tortillas are crisp and the cheese is melted. Time may vary by air fryer and tortilla size.

Rest and slice. Let quesadillas sit 1 minute so the cheese sets slightly. Slice into wedges.

Serve with toppings. Add salsa, sour cream, guacamole, cilantro, and a squeeze of lime. Keep it simple or pile it high—your call.