In a cast iron skillet, add the blueberries. Pour the lemon juice in and sprinkle the chia and stevia powder over the berries. Mix with a spoon.
In a bowl, mix together the almond meal, oats, cinnamon, stevia powder and ghee. Mix with your hands or a fork until the ghee absorbs the "flour" and starts to crumble.
Transfer the crumble over the blueberry mixture and cook in the preheated oven for 30 minutes.