Preheat oven to 350. Prepare ramekins with cooking spray or butter.
In a stand mixer or in a mixing bowl, combine all ingredients until large, moist clumps form in the mixture. You can do this with the stand mixer or with your hands.
Refrigerate mixture while you prepare your berries.
Place all berries in a mixing bowl, sprinkle sugar and lemon juice, if using, over the berries.
Stir to combine.
Divide the berries between the baking dishes, getting a good mixture of all the berries in each dish.
Top each baking dish with the crumble.
Bake for 35 minutes or until filling is bubbling and the crumble topping is golden brown.
Serve hot, warm or at room temperature with whipped cream or ice cream.