Use any combination of raspberries and strawberries, or feel free to sub some of them with blackberries or whatever you have. I recommend keeping the amount of blueberries at three cups to give it structure. You can use fresh or frozen berries. I buy extra berries in the summer months and freeze them for later. Make sure to clear any debris or stems off the berries before freezing and don't wash them.You can also spice up the topping: Add ¼ teaspoon or so of ground cinnamon to the topping when blending the dry ingredients.
Add all the berries to a saucepan along with the maple syrup and lemon juice, and bring the berries to a steady simmer. Simmer for about 8 minutes, or just until the strawberries are beginning to soften.
Cool for a few minutes and then transfer the berry mixture to 8 inch x 8 inch baking dish (or similar size).
Preheat your oven to 350°F.
Whisk the almond flour and salt in a bowl.
Add the oil, maple syrup, and vanilla extract, and lightly blend with a spoon or spatula until clumps of dough form into a crumble topping.
With your hands or a spoon, sprinkle the crumble evenly over the top of the berry mixture and bake for 10 minutes, or until the top is lightly browned.
Serve with yogurt, whipped coconut cream, or ice cream, or just have it solo.