Step 1: Sauté the Aromatics
Heat the olive oil in a large skillet over medium heat. Add the diced onion and bell pepper and cook for 4-5 minutes, until they begin to soften. Add the minced garlic (and jalapeño, if using) and cook for another 30-60 seconds until fragrant.

Step 2: Season the Chicken
Add the shredded chicken to the skillet with the vegetables. Sprinkle the chili powder, cumin, smoked paprika, salt, and pepper over everything. Stir well to coat the chicken and vegetables in the spices and heat through, about 2-3 minutes. Transfer this filling mixture to a bowl.

Step 3: Wipe the Skillet and Begin Assembly
Wipe the same skillet clean with a paper towel. This ensures you get a clean, crisp sear on the tortilla. Place the skillet back over medium heat. No additional oil is needed.

Step 4: Build the Quesadilla in the Pan
Place one tortilla in the dry skillet. Sprinkle a thin layer of cheese (about ½ cup) evenly over one half of the tortilla. This initial layer of cheese acts as a “glue” for the filling. Spoon half of the chicken and vegetable mixture over the cheese, then top with another generous handful of cheese. Finally, fold the bare half of the tortilla over the filled side, creating a half-moon shape. Press down gently with a spatula.

Step 5: Cook to Golden-Brown Perfection
Cook for 2-3 minutes, until the bottom is golden brown and crispy. Peek underneath by lifting it with a spatula. Carefully flip the quesadilla over and cook for another 2-3 minutes on the second side until it is also golden brown and the cheese is completely melted.

Step 6: Repeat and Rest
Remove the cooked quesadilla to a cutting board and repeat the process with the remaining tortillas and filling. For best results, let the quesadilla rest for 1-2 minutes before cutting. This allows the cheese to set slightly, preventing a volcanic cheese eruption when you slice it.

Step 7: Slice and Serve
Use a sharp knife or a pizza cutter to slice the quesadilla into 3 or 4 wedges. Serve immediately with your favorite dipping sides like sour cream, salsa, and guacamole.