Melt butter and mix with the following in a medium bowl: cocoa, sugar and salt
In a separate bowl, mix together: 1 egg beaten, 2 tsp vanilla, 1/4 cup coffee, 2T espresso vinegar
Add the egg mixture to the butter and mix well. Add in flour, mix until well combined but not past that as that will decrease the 'fudge' factor of the brownie.
Bake in a well-buttered dish for 15-20 minutes until a toothpick or knife comes out clean.
Frosting
Mix all of the ingredients together with beaters or in a food processor, then stir in the chocolate chips.
Frost the brownies when cooled completely. I like to store them in the fridge tucked behind things so no one knows they are there but me.