Set oven to 375F/191C.
In a 10 or 11 inch cast iron skillet, or casserole dish, mix together the ingredients for the filling. Set aside while you prepare the topping/crust.
In a mixing bowl, mix together all of the dry ingredients for the crust, then add butter, egg and vanilla bean. It should be a thick crumbly mix.
Add the topping to the top of the berries. Lightly spray the top with cooking spray (I recommend olive oil or butter flavored cooking spray).
Bake for 18 – 20 minutes, or until the top is golden brown and the berries have turned into a jam.
Let it cool for 5 – 10 minutes before enjoying! I enjoyed mine with 2% Greek yogurt.