A galette is a flat French tart or cake. After baking to a glossy sheen, the filling becomes a sweet-and-tart masterpiece.
On a piece of lightly floured parchment, roll out dough to a 16-inch-long oval (1/4 inch thick). Transfer dough and parchment to a baking sheet. Refrigerate until cold, about 30 minutes.
Process 1/4 cup sugar, the almonds, nutmeg, and salt in a food processor to combine. Gently toss with cherries.
Preheat oven to 375 degrees. Spoon cherries over dough, leaving a 2-inch border. Dot with butter. Fold in edges, pressing gently. Refrigerate until cold, 30 minutes.
Whisk yolk with cream; brush over edges of tart. Sprinkle with remaining 2 tablespoons sugar (or to taste). Bake until golden, 45 to 50 minutes.