Place all filling ingredients in a heavy-bottomed pot and stir to combine.

Cook on medium heat until fruit begins to soften and berries begin to burst, about 12–15 minutes, stirring frequently.

Remove from heat and transfer to a deep, oven-proof pie pan or casserole dish.

Preheat oven to 350°F (180°C).

Combine crumble ingredients in a medium-sized bowl, stirring with a fork until coarse crumbs form.

Sprinkle crumbs over filling, covering all the filling evenly.

Bake uncovered for approximately 45 minutes or until filling begins to bubble around the edges of the pan.

Remove from heat and allow to rest five minutes. Serve hot or cold.