Preheat your oven to 350. Grease a 9” to 10” pie pan or cast iron skillet with butter and set aside.
Pit and halve your cherries. You can do this with a cherry pitter or by hand.
Mix halved cherries with the other filling ingredients, stir well, and set aside.
To make the topping, grind the oats in a food processor or blender until somewhat fine.
Add in the flour, brown sugar, and cinnamon and mix well.
Mix in the butter until it has the texture of a dry cookie dough.
Stir the cherry filling again and pour into your prepared dish.
Crumble the topping evenly over the filling.
Bake for 45-50 minutes, or until the topping begins to turn a deep golden brown.
Let cool at least 30 minutes before serving.
