Cut each sheet of phyllo dough into four rectangles. Lay them on parchment paper and bake for about 3-5 minutes but make sure not to burn them (they do burn fast).
Using an electric mixer, whip up the egg whites with a pinch of salt
In a bowl mix the mascarpone and Greek yogurt with maple syrup and delicately add to the egg whites. Combine delicately with a spatula. Set in the fridge for at least 30 minutes
When you’re ready to serve place one brick on each plate. Using a table spoon or a pastry bag, put on one layer of mascarpone on each sheet. Place several blackberries on top then add another sheet of phyllo dough. Repeat this step, finish with one rectangle of phyllo dough
Decorate with some powdered sugar and serve very cold