Combine sugar, flour and cinnamon in a bowl. Add apples and toss. Arrange the apples to cover the pastry, leaving 1/2 inch around the edge.
For the topping, combine the flour, brown sugar, oatmeal, cinnamon and butter. Using a fork, combine to form a coarse crumb. Sprinkle over apples.
Bake at 375° for 35-40 minutes or until apples are tender and crust is golden brown. Remove from the oven and immediately drizzle with the caramel topping.
Serve warm with ice cream if desired.