• Pre-heat your oven to 370℉/180℃. Line an 8" Square Pan with greaseproof paper.
• In a small bowl, break up the dark chocolate and melt in the microwave in 20 second intervals, stirring in between to make sure it doesn't burn. Alternatively, set up a double boiler. Do this by placing a heatproof bowl over a small pot of simmering water. Add the chocolate to the heatproof bowl and stir until melted.
• In a large mixing bowl, whisk together melted butter, instant coffee and both sugars. Add in the eggs, one at a time and mixing in between. 
• Now, add the melted chocolate slowly and combine once again. 
• Add the flour and cocoa powder, fold gently into the wet mixture with a rubber spatula or wooden spoon until just combined. Pour into the lined tin.
• Bake 25 minutes until the top is shiny and it's still just a little wobbly in the middle. Let cool.

For the Frosting

• Make the frosting: Add the butter to a large mixing bowl. Beat with a whisk on high for a minute to soften.
• Add half the powdered sugar, whisk on high. Then add the remaining half and whisk everything on high until fluffy. Add powdered sugar/milk as required to meet your desired consistency.
• Spread the frosting over the cooled brownies. Then use a spoon to dollop on the caramel sauce, and swirl in just slightly. Slice and serve!