Mix oats, flour, brown sugar, salt, and cinnamon together in a medium sixed mixing bowl.

Cut butter into small cubes and cut into flour and oatmeal mixture until blended.

For the berries, mix the sugar, flour, and vanilla together and toss with the blackberries.

Spray a 9 x 13 baking dish with non-stick spray.

Spread berry mixture evenly in the bottom of the prepared pan.

Sprinlke the oatmeal mixture over the berries, evenly.

Bake at 350° for 45 minutes.

Then, remove from the oven and allow time to cool.

Enjoy with vanilla ice cream or whipping cream.