Cranberry upside-down cake

And yet more fun things to do with cranberries that aren't sauce!

From The New York Times:

FOR THE TOPPING:

4 tablespoons (1/2 stick) unsalted butter
3/4 cup brown sugar
9 ounces (2 2/3 cups) fresh cranberries
1/4 cup fresh orange juice

FOR THE BATTER:

1 1/2 cups all-purpose flour
2 teaspoons baking powder
1/4 teaspoon salt
8 tablespoons (1 stick) unsalted butter, at room temperature
1 cup sugar
1 teaspoon vanilla extract
2 eggs, separated
1/2 cup whole milk
1/4 teaspoon cream of tartar

To prepare topping: In a 9-inch round cake pan over low heat, melt butter and add brown sugar. Stir sugar until it dissolves, swirling pan to coat bottom. When sugar starts to caramelize, remove pan from heat and allow to cool.

In a small bowl, combine cranberries and orange juice. Toss to coat berries well. Spread berries evenly in pan, and sprinkle with any juice remaining in bowl. Set pan aside, and prepare the cake batter.

To prepare batter: Preheat oven to 350 degrees. In a large mixing bowl, sift together flour, baking powder and salt. Set aside.

Using an electric mixer, cream butter with sugar until pale, light and fluffy. Add vanilla, and beat in egg yolks one at a time, scraping bowl once or twice. Add flour mixture alternately with milk, ending with dry ingredients. Set batter aside.

Using electric mixer, whisk egg whites with cream of tartar just until whites are stiff enough to hold a slight peak. Fold whites into batter 1/3 at a time. Spoon batter into prepared pan, and spread it evenly over cranberries. Bake until top is browned and cake pulls away slightly from edges of pan, 25 to 35 minutes. Let cake cool for 15 minutes before turning onto cake plate.