Preheat oven to 350 degrees. Line a rimmed baking sheet with parchment paper and set aside.
Combine the berries, sugar and lemon zest in a bowl. Set aside to marinate while the oven preheats.
When the oven is ready, place the pie dough on the prepared baking sheet.
Top the dough with the fruit mixture, leaving a 2-inch border.
Fold over the dough edges.
Brush the dough with the egg white and sprinkle with raw sugar.
Bake for about 25 - 27 minutes or until the tart is cooked and slightly golden.
Dust with powdered sugar, garnish with fresh mint and serve immediately.