Seriously Simple: One-pot mocha brownie cake is easy and scrumptious
1/2 cup water
1 stick (1/2 cup) unsalted butter
1/2 cup unsweetened cocoa, like Droste or Scharffen Berger
2 teaspoons instant espresso like Medaglia D'Oro
1/4 cup buttermilk
1 egg
1 teaspoon vanilla
For the frosting:
1/2 stick butter
1/4 cup cocoa
...continued