Melt chocolate over a double boiler and let it cool to room temperature.

Preheat oven to 350 F. Line a 8x8 inch baking pan with parchment paper or foil.

Transfer chocolate to the bowl of a stand mixer with paddle attachment. Add butter and beat until incorporated. Add sugar, then slowly add eggs and egg whites, mixing on medium - low speed, until incorporated.

Add in instant coffee and flour. Mix until just combined, do not over mix.

Pour batter into baking pan, leaving 1/2 cup a side.

For the swirl: In a bowl, combine Mascarpone, sugar, egg whites, vanilla and liqueur (optional). Mix until incorporated.

Using a spatula, spread Mascarpone mixture over the chocolate one. Spoon over the remaining brownie batter and using a fork of wooden skewer, swirl the brownie batter into the Mascarpone layer.

Bake for 35 minutes (Baking time may vary), until center is set and brownies start to pull away from the sides of the pan. Let it cool completely in the pan, before slicing and serving.

Serve with a scoop of Tiramisu ice cream.