Preheat your oven to 375℉.
Add the berries (if using frozen, make sure they are straight out of the freezer, not thawed) to a bowl then toss with the other filling ingredients until the berries are all evenly covered. Then, add the berry mixture to a small baking dish.
In a separate bowl, combine the crumble topping ingredients and mix until clumps form.
Crumble the topping on top of the berry mixture.
Bake the crumble for 30-40 minutes (depending on your oven, be sure to check on it!). It will be ready when the berry juices are bubbling slightly and the top is golden brown.
Serve with ice cream if you'd like. It's best served right out of the oven!