Preheat your oven to 350°F and line a 6-inch square baking pan with parchment paper, lightly greasing it.
In a saucepan over low heat, melt the butter with the sugar. Stir in the milk and espresso powder, then remove from heat. Add the chocolate and stir until melted and smooth. Let it cool a bit.
In a large bowl, sift together the flour, cocoa powder, and sugar.
Mix the cooled chocolate mixture into the dry ingredients until well combined.
Pour half of the brownie batter into the prepared pan.
Mix the sugar into the coffee and place it in a bowl. Dip each sponge finger into the coffee mixture, then layer them on top of the brownie batter.
Spread the remaining brownie batter over the sponge fingers and bake for 20-25 minutes, or until the top is set.
To make the frosting, beat the cream and powdered sugar until soft peaks form. Then add the cream cheese and beat until smooth.
Once the brownies have cooled, spread the frosting over the top and finish with a dusting of cocoa powder.