The galette looks and sounds fancy, but with its free-form shape, it's ridiculously easy. Rainier cherries have pale, creamy flesh and are larger and sweeter than Bing cherries. If you opt for another variety, add an extra tablespoon of sugar.
1/2 (14.1-ounce) package refrigerated pie dough (such as Pillsbury)
Line a baking sheet with parchment paper. Unroll pie dough onto parchment, and roll to a 12 1/2-inch circle. Combine 1 tablespoon sugar and 1 1/2 teaspoons cornstarch, stirring with a whisk. Sprinkle cornstarch mixture over dough, leaving a 2-inch border.
Combine the cherries, remaining 2 tablespoons granulated sugar, rind, and juice; toss well to coat. Arrange cherry mixture over dough, leaving a 2-inch border. Fold dough border over cherries, pressing gently to seal (dough will only partially cover cherries). Brush edges of dough with buttermilk. Sprinkle turbinado sugar over cherries and edges of dough. Bake at 400° for 25 minutes or until dough is browned and juices are bubbly. Remove from oven; cool on pan at least 20 minutes before serving.