Preheat oven to 350 degrees

While oven is preheating, peel and dice apples

Mix apples with the sugar and cinnamon in a bowl, making sure the apples are evenly coated

Pour mixture into a 8"x8" baking pan

In a separate bowl, combine the melted butter, oatmeal, brown sugar and flour

Sprinkle the crumble mixture over top of the apples, making sure to cover everything and evenly coating the apples

Bake for 45 minutes or until apples are tender

Serve hot!