Plum Upside-Down

Instructions

1. 1

   With the rack in the middle position, preheat the oven to 180 °C (350 °F). Butter and line a 20 cm (8-inch) springform pan with parchment paper. Place on a baking sheet.

2. 2

   In a bowl, combine the flour, baking powder and baking soda. Set aside.

3. 3

   In another bowl, cream the butter and sugar with an electric mixer. Add the egg and egg whites, one at a time, and beat until the batter is smooth. At low speed, add the dry ingredients alternately with the buttermilk. Set aside.