In a 25-cm (10-inch) cast iron skillet, bring the sugar, water and butter to a boil. Simmer over high heat until golden brown. Add the apples and stir to coat. Sauté for 2 to 3 minutes. Arrange the apples, core side up. Cover the apples with the pie crust, folding the dough inside the skillet. Bake for about 50 minutes or until the crust is golden brown. Let cool for 5 minutes. Flip onto a serving platter. Serve warm with vanilla ice cream.
