Preheat the oven to 350 degrees F.
Prepare an 8 to 9-inch cast iron skillet or baking dish by coating with a thin layer of coconut oil.
Mix all the filling ingredients together in a large bowl, then pour the filling into the skillet, spreading out evenly.
Using a food processor or blender, prepare the crumble. Pulse the pumpkin seeds, walnuts, and pecans just enough to break down into smaller pieces. You can also do this step by hand, roughly chopping all nuts and seeds, leaving a finer texture.
Add remaining ingredients and pulse several more times until you get a crumbly texture. Sprinkle the crumble over the top of the berries in the skillet.
Bake until berries are bubbling, about 40-45 minutes.
Let cool for as about 5 minutes, then top with vanilla bean ice cream and serve! :)