Take a saucepan with little water and place a bowl in it for using as a double boiler. In the bowl, add egg yolks, beat well. Whisk in the sugar till well combined. Add lemon zest and juice and mix well. Place bowl on simmering water. Keep stirring for approximately 10-11 minutes. Take off bowl from the water and add the softened gelatin (to soften add gelatin to a bowl of cold water and keep aside for a while) and stir well. Keep aside till the mixture cools slightly. Bet eggs with a blender till it forms peaks. Add the eggs to the mixture when it cools and fold in.

Take a bowl. Line the bottom of the bowl with the ladyfingers. Pour in the custard mixture. Keep in the refrigerator for approximately 1 to 1 ½ hrs. Serve chilled.

For the topping:
Beat whipped cream and sugar in a bowl (add in the sugar little by little while beating and fill into a pastry bag and pipe).