In a food processor or with a pastry cutter (or your hands!), slowly pulse together butter, flours, 2 teaspoons of sugar, and salt. Once just barely combined and there are still a few chunks of butter, slowly add in cold water until a shaggy dough forms.
Turn the dough out onto the counter and knead it together for about a minute. Wrap it in saran wrap and put it in the fridge for 1 hour.
Preheat the oven to 425 degrees.
When the crust is chilled, line a baking sheet with parchment paper and roll out the dough into a shaggy circle.
Toss together the frozen blueberries, 1 tablespoon flour, lemon juice, zest, ginger, and vanilla. Mound them into a heap in the middle of the dough and fold up the edges so it stays a bit contained. Brush the crust with a beaten egg yolk to make it shiny.
Reduce the heat of the oven to 400 degrees and place the tart in the oven. Bake the tart for 40-45 minutes. Allow it to cool a bit before serving.
Recipe by Uproot Kitchen at https://uprootkitchen.com/2015/06/21/wild-blueberry-tart/