1. Peel and core apples; cut in half lengthwise. Toss together apples and sugar; place in a 12-inch cast-iron or ovenproof skillet.
2. Cook over medium-high heat, stirring often, 20 to 30 minutes or until apples soften and start to caramelize.
3. Unfold and stack pastry sheets on top of each other on a lightly floured surface. Roll to a 12-inch square. Place on top of cooked apples, with pastry corners overlapping sides of skillet.
4. Bake at 450° for 10 to 12 minutes or until dark golden brown.
5. Cool on a wire rack 10 to 15 minutes. Carefully invert tart onto a serving plate; remove skillet. Cut tart into wedges, and serve with Ol' South Custard.