Grease an 8x8 baking pan and preheat oven to 375F.

In a small bowl or cup combine granulated sugar and cinnamon. In a medium bowl combine cinnamon-sugar with the sliced apples and stir to coat evenly.

In a separate bowl, mix together oatmeal, flour and brown sugar. Cut the butter into small cubes and then add to the oatmeal mixture. Mix together until crumbly – a fork or pastry blender will help break the butter into even smaller pieces.

Place the apples into the prepared pan. Layer the oatmeal mixture on top.

Bake in preheated oven for 30 minutes.