Cooking School/ The Peach Galette

Ingredients:
For the Crust:
1 ½ Tablespoons sour cream
3 Tablespoons ice water
½ cup flour
2 Tablespoons yellow cornmeal
pinch of salt
4 Tablespoons cold unsalted butter, cut into 4 pieces
For the Filling:
3-4 ripe peaches
1 Tablespoon [...]