Espresso cake with fudge frosting

I used 2/3 of a Betty Crocker Sponge mix and omitted the sugar from the syrup as the icing is so sweet. As I did not frost all over the cake I just made half the frosting and used inside and on top with some chocolate dribbled over.

Packet Cake mix made up using 2 eggs

1/3 cup hot, freshly brewed espresso
1/3 cup sugar
1/3 cup dark rum

In a bowl, stir together the espresso and sugar until the sugar dissolves. Add the rum and let cool to room temperature. Spread over the sliced cake.

6 ounces unsweetened chocolate, melted and cooled
4 cups confectioners’ sugar (no need to sift)
8 ounces unsalted butter, at room temperature
4 tablespoons half-and-half or whole milk
1 tablespoon vanilla extract

Combine all of the ingredients until the frosting is smooth and decorate the cake.