Mocha Upside-Down Cake

Preheat oven to 350 degrees F (175 degrees C). Grease an 8-inch baking pan.

Combine butter and unsweetened chocolate in a microwave-safe bowl; heat in the microwave until melted, 20 to 30 seconds. Stir milk and vanilla extract into chocolate mixture.

Mix flour, 3/4 cup white sugar, baking powder, and salt together in a separate bowl; stir in chocolate mixture until batter is smooth. Pour batter into the prepared pan.

Stir coffee, brown sugar, 1/2 cup white sugar, and cocoa powder together in a bowl; pour over batter.

Bake in the preheated oven for 30 minutes. Cool cake in the pan for 10 minutes. Turn cake onto a serving platter.