Preheat oven to 350°F/177°C. Grease and line a 9-inch oven-proof glass baking dish.
In a bowl, whisk together all brownie ingredients. Pour into the prepared baking dish. Bake for 25-30 minutes or until set. Cool slightly and refrigerate. Once the brownie is set, cut crosswise to make two layers. Set aside.
Prepare Cream Mixture: In a bowl, whisk together eggyolks and sugar until well blended then cook bain-marie style. Make sure water does not touch the bottom of the bowl. Cook until creamy white. In another bowl, beat together mascarpone, cream cheese, coffee liqueur, and vanilla until soft and fluffy. Blend together eggyolk mixture and cheese mixture until well blended. Set aside.
Whip cream until fully aerated, then lightly fold into the mixture. Set aside.
In a sauce pan, heat up sugar and water and bring to a boil then simmer until syrupy like. While cooking the syrup, whisk eggwhites until soft peaks form then slowly add in the syrupy liquid. Keep whisking until aerated and stiff. Fold into 3 batches the whisked eggwhites into the cheese and cream mixture, Set aside for later use.
Prepare Coffee Mixture: Combine in a bowl all the ingredients for the coffee mixture.
To Assemble: Spread 1/3 of the cream mixture on the bottom the glass dish. Place one brownie layer, brush generously with coffee mixture. Spread another third of the cream mixture and top with second brownie layer, brush again with coffee mixture. Spread remaining cream. Refrigerate to set. Garnish and dust top with cocoa powder before serving.