Strawberry Buttermilk Upside-Down Cake

Position a rack to the center of the oven and preheat oven to 350°F. Prepare a 9-inch nonstick cake pan. If your pan is not nonstick, spray the pan generously with cooking spray.

In a small saucepan, combine 4 tablespoons of the butter, the brown sugar and a pinch of salt. Stir over high heat until the sugar has dissolved. Boil for 2 minutes. Then pour the caramel into the bottom of the prepared cake pan and spread into an even layer. Arrange the strawberry halves over the caramel in a circular pattern, leaving little to no space between the berries.

In a medium bowl, sift together the flour, baking powder, baking soda and 1/4 teaspoon of salt. Set aside.

In the bowl of an electric mixer, beat together the remaining 8 tablespoons of butter with the granulated sugar until light and fluffy, about 2 minutes. Beat in the vanilla and the egg yolks. Reduce the mixer speed to low and alternately add the flour mixture and the buttermilk into the creamed mixture in three batches. When just a few streaks of flour remain, fold the batter by hand until smooth.

In a clean bowl, beat the egg whites and the cream of tartar to firm peaks. Stir about a quarter of the beaten whites into the batter to lighten it, then gently fold in the rest of the whites until the batter is smooth and well-blended.

Pour the batter over the fruit in your pan and smooth the top. Bake until a toothpick inserted in the center comes out clean, 45 to 50 minutes.

Let the cake cool in the pan for 20 minutes before inverting it onto a serving platter. Serve warm or at room temperature, garnished with unsweetened whipped cream.