Preheat oven to 160C fan forced 170C regular
Prepare the base by combining stevia, coconut flour and chia seeds, then add berries and stir well.
Transfer berry mix to small baking dish and spread evenly.
Prepare crumble by mixing coconut flour stevia and baking powder together. Add butter and combine well.
Top the berry mixture with crumble and bake for 8-10 minutes, until golden brown on top.
Remove from the oven and allow to cool for 10 minutes before serving.