If using fresh berries rinse them and dry them on kitchen paper. If using frozen defrost them then dry them on kitchen paper.
Instructions
Start with the base: In a bowl, mix the flour, the ground almonds, the sugar, the xanthan gum and the salt. Add the vegan butter and the almond puree, rubbing by hand into the flour and mixing until well combined. In a small bowl mix the flaxseeds with the warm water (it will become like a gel) then add it to the base and mix again by hand. Squish the dough until it becomes homogenous, roll it into a ball and cover it with wrap. Rest it in the fridge for at least one hour.
To make the berry filling: mix them with the sugar and the cornflour. Set aside.
To make the crumble, mix all the dry ingredients listed in that section. Gently melt the coconut oil and rub it in with your fingers until you get a sandy texture. You may need to add more flour a spoon at a time.
Pre-heat the oven to 175C. Roll out the pastry into your fluted tin, pierce the bottom with a fork. Add the berry filling, then sprinkle on the crumble topping. Bake for 40 minutes, then for another 15 minutes at 150C.