We prepare four of the tortillas by quickly placing them into the oil to coat one side (we could have also used a pastry brush). We reserve each on a large plate, oil-side-up.
We pour the rest of the oil onto the foil and spread out to coat an area large enough for the four quesadillas. We place the rest of the tortillas on the oil-covered sheet pan and rub around to coat the bottom with the oil. We spread on 2-3 tablespoons of the cheese mixture and top with the reserved tortillas, oil side up. We reserve the remaining cheese for the topping of the baked quesadillas. We place the pan in the pre-heated oven.
We cook for about 5 minutes. We want the bottom tortilla to start to brown. We carefully flip over with a spatula and return the sheet pan to the oven. We cook for another 5 minutes or so until the tortillas are crispy and the cheese is melted.
We serve the quesadillas with salsa and the extra cheese.