For the expresso extract:Stir the coffee powder and boiling water together in a small cup until blended.Set aside.

For expresso syrup: Stir the water and sugar together in a small saucepan and bring just to a boil.Pour the syrup into a small heat proof bowl and stir in 1 tbsp of the expresso extract,set aside

For the filling : put the mascarpone,sugar,vanilla in a large bowl and whisk just until blended and smooth.Whip the heavy cream until it holds firm peaks.Stir about one quarter of the whipped cream into the mascarpone. Fold in the rest of the whipped cream with a light touch.

To assemble the Tiramisu: Place one layer of finger biscuits in the small individual serving bowls.Soak the layers with about one third of the expresso syrup.Smooth some of the mascarpone cheese over the layers and gently press the chopped chocolate into the filling.

Put the second biscuits layer over the chocolate and soak the top of it with half the remaining expresso syrup.Then turn the layers over with soaked side down over the filling. Soak the top of the biscuits with the remaining syrup.

For the frosting:Whisk 1 to 1 1/2 tbsp of the remaining expresso extract into the remaining mascarpone filling.

Refrigerate the cake.With a long spatula, smooth the frosting around the sides of the cake and over the top.

Sprinkle cocoa powder on the top.Refrigerate the cake for at least 3 hours before serving.

Do try it.It's a piece of heaven.