Preheat the oven to 350°F.
Place the apple slices in a greased ramekin. Set aside.
In a small bowl, mix together the flour, brown sugar and cinnamon. Mix in the butter until the mixture resembles coarse crumbs. Mix in the oats.
Sprinkle the oat mixture on top of the apples and bake in the preheated oven for 35-40 minutes, or until the apples are tender. Top with ice cream and enjoy!