Gluten-Free Strawberry Galette

To prepare pastry crust, lightly spoon flour into dry measuring cups, and level with a knife. Combine flour and next 3 ingredients (through salt) in a food processor; pulse two times. Add butter to flour mixture; pulse 4 to 5 times or until mixture resembles coarse meal. With processor on, slowly add buttermilk through food chute; process just until dough forms a ball. Gently press dough into a 4-inch circle on plastic wrap; wrap tightly and refrigerate for 30 minutes.
Preheat oven to 350u0b0 F. Unwrap dough and place on a sheet of parchment paper, dusting with flour if dough feels a little tacky to the touch. Cover with another sheet of parchment paper and roll dough into a 15-inch circle. Carefully peel off top piece of parchment and slide dough with bottom sheet of parchment onto a baking sheet.
To prepare filling, whisk together almonds, Cup4Cup flour and 1/4 cup sugar. Spoon onto prepared pastry, leaving a 2-3-inch gap around the edges. Combine strawberries with 1 tablespoon of sugar, balsamic vinegar and optional almond extract, then spoon carefully onto the almond flour mixture.
Using a bench scraper, carefully fold edges of pastry up and over the strawberry filling. If you see any rips, pinch to seal. Lightly sprinkle edges of dough with turbinado sugar.
Bake at 350u0b0F for 50 minutes to one hour, or until pastry is golden brown and strawberry juices are bubbling. Carefully slide galette still on parchment paper onto a rack. Cool to room temperature before serving.