Ingredients

3 cups all-purpose flour
¼ cup sugar
1 tbsp. baking powder
½ tsp. baking soda
¾ tsp. salt
1½ sticks (12 tbsp.) unsalted butter, cold and cut into cubes
1 large egg, beaten
1 tsp. vanilla extract
¾ cup buttermilk, plus more for brushing
1-2 ripe peaches, sliced thin

For the cinnamon-sugar:
2 tbsp. sugar
¾ tsp. ground cinnamon