Combine the salt, sugar, and flour in a food processor. Pulse until thoroughly blended. Divide the butter into 1/4-inch segments and add the sections to the mixture in the food processor. Continue to pulse until well blended.
Add the shortening, about 1/8 cup at a time. Pulse until the mixture has the consistency of cornmeal. Pour in the water and continue to pulse until a dough begins to form. Remove the dough from the food processor. Wrap the dough in plastic wrap and chill it for a minimum of 1 hour.
Remove the dough from the fridge and let it sit for 5 minutes. Prepare your work surface by lightly sprinkling the counter with flour and applying a light coating of flour to your rolling pin.
Using the rolling pin, roll a disc of dough to a 12-inch circle. Use a bench scraper to lift the dough from the counter periodically to prevent sticking.
Carefully transfer the disc to a baking tray lined with parchment paper or Silpat baking mat. Set aside.
Preheat your oven to 400 degrees.
Wash and dry your apples. Peel and core your apples, then thinly slice. In a medium bowl, toss the sliced apples with brown sugar, gluten-free flour, cinnamon, nutmeg, and vanilla extract, until well coated. Set aside.
Arrange the apple slices in the center of the disc on the prepared baking sheet. Make sure to leave a 2 - 3-inch border around the apple slices.
Fold the overhang of the dough over the apples, seal the overlaps with your fingers by tucking them in.
In a small bowl, combine the heavy cream and egg yolk with a whisk. Using a pastry brush, lightly brush the crust of the galette with the egg wash, and sprinkle with Turbinado sugar. Cube 1 tablespoon of butter, then place the cubes of butter atop the apples in the center.
Bake for 30-35 minutes or until the apple filling is tender, and the crust is golden brown. Allow the galette to cool slightly before serving. Drizzle with caramel sauce or a scoop of vanilla ice cream. Enjoy!
You can purchase your Cup4Cup Multipurpose Gluten-Free Flour online.
Check out these essential baking tools every home baker needs.
Feel free to swap out gluten-free flour with all-purpose flour.
A pie crust made from scratch is not a requirement to enjoy an apple galette. You can find premade crusts in your grocery store's freezer aisle or you can purchase a pie crust mix. To prepare, follow package directions.