Crust:

1. Mix dry ingredients: In a medium mixing bowl, whisk together the gluten-free all-purpose flour, almond flour, granulated sugar, and salt. 
2. Add butter: Use the large-hole side of a box grater to grate in the salted butter. Lightly toss butter with dry ingredients to coat, and then use a pastry cutter to disperse the butter into the dry ingredients, making sure no large chunks remain. 
3. Add liquid ingredients: Sprinkle 3 ounces ice water and the almond extract over the dry ingredients. Use hands to gently bring the dough together into a ball; it should be neither dry nor sticky. Add up to an additional 1 ounce water if needed. 
4. Chill: Transfer dough to a large piece of plastic wrap, flatten into a small disc, and wrap tightly. Refrigerate for 1 hour while prepping filling.

Almond Filling: 

1. Combine ingredients: In a small mixing bowl, whisk together almond flour, powdered sugar, and a pinch of salt. Add heavy cream and almond extract. Use a spatula to mix in until the mixture comes together. 
2. Cut in cornstarch: Add cornstarch and blend in with a pastry cutter; the mixture should be crumbly. Cover with plastic wrap and set aside. 

Stone Fruit Filling:

1. Mix filling: In a large mixing bowl, whisk together granulated sugar and cornstarch. Add sliced fruit and gently toss in until completely coated in the sugar mixture. Cover with plastic wrap and refrigerate until ready to assemble galette. 

Assembling:

1. Roll dough: Cut a piece of parchment paper to the size of a standard cookie sheet and dust generously with gluten-free flour. Transfer chilled dough to parchment, dust surface with flour, and roll out to a 12” round, adding more flour as needed to prevent sticking. If desired, trim outer border of dough to form a circle with clean edges.
2. Add toppings: Leaving a 1 ½” border around the outer edge of dough, sprinkle almond filling evenly over center section. Arrange sliced fruit in a concentric pattern on top, working from the outside in towards the center, and slightly overlapping each fruit slice with the next. Reserve leftover juice for brushing on fruit before baking. 
3. Shape galette: Gently fold and pleat edges of dough over outer border of fruit filling. If dough starts to tear while doing this, refrigerate for just a few minutes before reattempting. 
4. Chill: Carefully slide or lift parchment onto baking sheet and transfer galette back to refrigerator to chill while preheating oven.
5. Prep for baking: Preheat oven to 400ºF. Just before baking, brush crust with heavy cream and sprinkle with sliced almonds and turbinado sugar. Brush fruit filling with leftover juice.
6. Bake: Bake galette in preheated oven for 30-35 minutes, until crust is golden. Serve warm, with whipped cream or vanilla ice cream.