Prepare the dough. Add stevia, coconut flakes, flour and vanilla to the bowl with the yolks. Pour in the milk and whisk until smooth. Beat the egg whites in a separate bowl until fluffy. Add the egg whites to the mixture and stir.
Bake the pie. Transfer the dough into the pan, spread the blackberries on top. Bake the pie in the oven preheated to 180 degrees for 30 minutes, checking the readiness with a toothpick.