Beat butter and sugar in a bowl until frothy. Mix flour with baking powder and stir. Add flaxseed egg, milk, apple cider vinegar, vanilla and cinnamon, mix. Pour the dough into the springform and smooth.
Crumbles
Distribute blackberries evenly on the dough. For the crumbles knead flour, sugar and butter with your hands. Then spread the crumbles on the cake. Cover the cake as desired with chopped almonds or almond slices.
Put in the oven and bake for 30-40 minutes. Make a stick sample. If no dough gets stuck, the cake is ready.
Cool on a wire rack.
Who likes to dust the cake with powdered sugar.
Notes
If you like other fruits, you can use other fruits or berries depending on the season. Rhubarb, cherries, plums or even apricots. Depending on the sweetness of the fruit I add more or less sugar.