Use this recipe as a topping for our Pain Perdu, Meringue Cups, and Almond-Polenta Cake.
Divide ingredients in half, and work in two batches. Melt butter in a 10-inch skillet over medium-high heat. Add apples and cinnamon. Sprinkle with sugar; toss to coat. Saute until apples are browned, about 5 minutes, tossing often. Transfer to a gratin dish. Serve warm.
Apples can be prepared up to eight hours ahead; reheat in a 450 degree oven.