Deluxe Butter Flaky Pastry Dough (Pâte Brisée)

1. In a large bowl, with a rubber spatula, combine the all-purpose flour, granulated sugar or powdered sugar, and salt.
2. With a pastry blender, cut in the COLD unsalted butter. Move fast so the butter doesn't soften.
3. Next, cut in the shortening with the pastry blender. The mixture should have coarse crumbs and pea-sized pieces. DO NOT let it become soft and clumpy.
4. Sprinkle 3 Tablespoons of ice cold water over the butter and shortening mixture.
5. Use the rubber spatula to work in the water so it looks evenly damp and clumps up into small balls.
6. With the flat side of the rubber spatula, press down. Do the galette dough balls stick together? If not, add 1 Tablespoon more of water over the top.
7. After mixing in the water, the dough should have a rough look to it.
8. Shape the dough into a flat, round disk and wrap it in plastic wrap.
9. Refrigerate the wrapped dough for 30 minutes (or up to two days). You could also pop it into the freezer for up to six months (but thaw completely before use).
10. While the dough is chilling, move the oven rack to the lower third of the oven.
11. Heat the oven to 400*.
12. Once the dough has been chilled, roll it out on a floured work surface to form a 13" circle.
13. Note: I tend to place a layer of parchment paper on a rimless cookie sheet and then roll the dough on the cookie sheet, shaking off the excess flour. Or, you can transfer the dough to the rimless cookie sheet.
14. Next, you'll combine 1 1/2 cups blueberries, raspberries, or thinly peeled peaches from the center — leaving a 2" to 3" border around the edge. This is important, as you'll see in a moment.
15. Sprinkle 2 Tablespoons of granulated sugar over the fruit.
16. Slice 1 Tablespoon cold, unsalted butter and scatter it over the fruit.
17. Fold the exposed edges of the dough over the fruit, so you still see the fruit in the middle, but are pleating the edges.
18. Brush the dough with milk and sprinkle with 1 to 2 teaspoons of coarse sugar (thicker sugar).
19. Bake 400* for 25 to 35 minutes or until golden brown.
20. Let cool on a wire rack. Serve warm or at room temperature.