Pie lovers watch out! This Mixed Berry Galette is as delicious as pie but way easier to make. No baking dish required.
Put cold butter, flour, salt, and sugar in your food processor and pulse for a few seconds. Pea sized butter flakes should be still visible. Add one tablespoon water after another and pulse for 1-2 seconds after every tablespoon. Then add one tablespoon of milk after another and pulse for 1-2 seconds after every tablespoon. Form pie crust into a ball without kneading. Flatten and wrap in plastic foil. Refrigerate for at least 1 hour up to 2 days.
Preheat oven to 425°F (190°C). Line a large baking sheet with parchment paper and set aside.
Prepare the filling as the oven preheats. Therefore, mix berries, sugar, cornstarch, and lemon juice together in a bowl. Set aside.
Roll out dough into a circle with 1/8 inch (0.4cm) thickness and transfer it onto the prepared baking sheet. Spoon berries without any liquid in the center of the dough, leaving a 2-3 inch border all around. Fold edges over berries and press gently to seal the edges. Brush edges with egg white and coarse sugar. Cut butter into small flakes and add on top of berries. Bake for about 25-30 minutes until crust is golden brown. Allow cooling at least 15 minutes before slicing and serving.