1/2 Granny Smith apple, quartered, cored and thinly sliced
Cooking spray or about 2 teaspoons vegetable oil
Sprinkle one half of each tortilla with about 2 tablespoons of cheese. Layer turkey breast and apple slices on top, followed by remaining cheese. Fold bare half of each tortilla down over the filling, pressing firmly.
Coat large skillet with cooking spray or brush with oil. Place over medium-low heat.
Add quesadillas to skillet and cook, pressing down with a spatula occasionally, until browned on the underside, 2 to 3 minutes. Turn over with a spatula and cook until browned on second side and cheese is melted, 2 to 3 minutes longer.