First, prepare the coffee by adding the hot water to the instant coffee and then let it cool.
In a bowl, take the whipping cream and the sugar together.
Then using an electric mixer whip up the cream and sugar together until soft peaks form.
Now add the mascarpone and the vanilla essence to the cream and continue to whip until the mascarpone and cream has mixed up nicely.
Dip ladyfingers in coffee and place in a 6x10 inch pan to make the first layer. Don't let the cookie soak too much otherwise they will fall apart, just a quick dunk in the coffee is enough.
Now spread half of the cream mixture on top of the first cookie layer and repeat the process with the second layer of ladyfingers and cream mixture.
Finally, dust the top of the cake with some cocoa powder using a sieve and refrigerate for at least 4-6 hours or overnight.