The classic French apple tart was created by accident at the Hotel Tatin just south of Paris by the two owners, who were sisters. Somehow, it was baked upside-down!
Preheat oven to 350. Use an inverted cast-iron skillet to draw a circle with a knife on a sheet of frozen puff pastry. Place the skillet over low heat, and cover the bottom with a thin layer of sugar. Allow to melt slowly (do not stir caramel, or it will crystallize). When dark brown, remove from heat and drop in a tablespoon of butter. Swirl around by moving pan, and set aside.Peel and cut apples around core into large chunks, or core them and slice in half. Place cut sides up in caramel. Lay pastry over top, pierce in the middle with a knife, and bake for about 40 minutes or until apples are tender. While hot, place a plate over skillet and flip tart quickly onto it (faites attention—the caramel can burn you).