Keep a pot quarter filled with water (double broiler process) on heat, in a metal bowl put egg yolks and castor sugar, keep on the pot should not immerse in. Keep on whisking egg and sugar, on low flame. Cook for 10 mins and whisking. Remove from flame and whisk it till it's thick.
Let it cool, add mascarpone and essence and beat well, keep aside.
In another bowl beat whip cream till peaks formed now add this in mascarpone mixture and fold in well, keep in fridge.