Preheat the air fryer: Set to 375°F (190°C). This helps the tortillas crisp faster and more evenly.

Cook the beef: Warm a skillet over medium-high heat. Add ground beef and break it up with a spatula. Cook until no longer pink, about 5–7 minutes. Drain excess fat if needed.

Add aromatics and seasoning: Stir in diced onion and cook 2 minutes. Add garlic and cook 30 seconds. Sprinkle in taco seasoning and 2–3 tablespoons water. Stir until the beef is coated and glossy. Taste and adjust salt and pepper.

Prep the tortillas: Lay tortillas on a board. Sprinkle a generous layer of cheese on half of each tortilla.

Add the beef: Spoon a thin, even layer of seasoned beef over the cheese. Don’t overfill—about 1/3–1/2 cup per quesadilla is plenty. Add any optional veggies or jalapeños now.

Top with more cheese: A light sprinkle helps glue everything together. Fold tortillas in half to form half-moons. Press gently.

Oil lightly: Spray both sides of each folded tortilla with oil. This gives you that golden, crisp finish.

Air fry in batches: Place quesadillas in the air fryer basket in a single layer. Don’t overcrowd. Cook 4–6 minutes total, flipping halfway, until the tortillas are golden and the cheese is fully melted. Time varies by air fryer model and tortilla thickness.

Rest and slice: Let the quesadillas sit 1–2 minutes before slicing. This helps the cheese set and keeps fillings from spilling.

Serve: Cut into wedges. Add salsa, a dollop of sour cream or Greek yogurt, guacamole, and a squeeze of lime.