NOTE: this makes TWO galette crusts! I highly suggest following this recipe and making two - stick one in the freezer so you have it when needed. You can freeze it for 3 months!
Add the flour, sugar, cinnamon and salt to a food processor and pulse just until combined. In a small bowl, whisk together the egg, vinegar and water. Add the cold butter pieces into the food processor and pulse until small coarse crumbs remain. Sprinkle the water/egg mixture over the flour and pulse again until the dough comes together.
Remove the dough with your hands and wrap it in plastic wrap. This dough makes enough for 2 galette crusts, so separate it into 2 sections now, – or separate it after it’s refrigerated.
Refrigerate the dough for 30 minutes. Freeze one of the other balls of dough!
After 30 minutes, preheat the oven to 400 degrees F. Remove one of the crusts from the fridge.
Combine the blueberries, raspberries and strawberries in a large bowl. Sprinkle the sugar and flour over the fruit and toss it well. Let sit until ready to use.
Place the cream cheese in a bowl. Beat with a hand mixer on medium speed until creamy and smooth. Beat in the sugar, egg, vanilla extract and a pinch of salt. Beat until combined and smooth.
Roll one of the pie crusts into a… “rustic”shape – like a big rectangle or circle with ragged edges, until it is about 1/4 inch thick. Place the dough on a parchment-lined baking sheet.
Spread three quarters of the cheesecake filling mixture on the dough, leaving a 1-inch border. Place the berries on top of the filling. Once the fruit is layered, fold the crust over top of it - it doesn’t have to look perfect or fancy. Dollop some of the remaining cheesecake filling over the berries.
Brush the crust with the beaten egg wash. Sprinkle with the coarse sugar.
Bake the galette until the crust is golden and the fruit is syrupy, about 40 to 45 minutes. Let it cool slightly before slicing and serving with a fresh mint leaf.