Black Forest Upside-Down Cakes

Preheat oven to 350 degrees. Place 1 tablespoon butter, 1 tablespoon brown sugar, and 1/2 teaspoon cherry juice in the bottom of each of two 8-ounce ramekins. Microwave ramekins until butter and brown sugar are melted and bubbling, about 1 minute. Arrange cherries in a tightly packed layer in the bottom of each ramekin.

In a small bowl, whisk together flour, cocoa, baking powder, and salt. In another small bowl, stir together 2 tablespoons butter and 1/3 cup brown sugar with a wooden spoon until light and fluffy, about 3 minutes. Stir in egg yolk, then flour mixture and milk. Divide batter between ramekins.

Place ramekins on a rimmed baking sheet. Bake until a toothpick inserted in center of a cake comes out with only a few crumbs attached, about 30 minutes. Let cool on a wire rack, 20 minutes. Meanwhile, in a small bowl, beat cream, 1 tablespoon brown sugar, and rum until soft peaks form. Run a paring knife around edge of each cake and invert onto a plate. Serve cakes with rum whipped cream.