Soak the gelatine in a bowl of cold water. Wash the lemons, grate dry and thinly grate the peel. Halve the lemons and squeeze the juice.
Separate eggs. (It is best to put them in mixing bowls immediately.) Put the egg whites in the refrigerator until they are ready for use.
Whisk the egg yolks and sugar in a mixing bowl with the whisks of the mixer for 5-8 minutes until thick and creamy. Stir in lemon juice and zest.
Squeeze the gelatine by hand. Then dissolve in a small pot at very low heat while stirring. Do not let it get too hot, otherwise it will lose its gelling power. Remove from the stove.
Immediately stir in approx. 3 tbsp. egg yolk mass bit by bit into the warm gelatine.
Using a dough scraper, stir the gelatine mix completely into the remaining egg yolk mass. Refrigerate the bowl until the mixture begins to gel (= solidifies; takes 30-40 minutes). Tip: Stir from time to time.
The egg yolk mass is gelled? Here we go: Beat the egg whites with 1 pinch of salt with the whisks of the mixer until stiff, until small peaks of egg white appear. Whip the cream until stiff as well.
Carefully fold the cream first, then the beaten egg white in portions into the jellied mass with a dough scraper. Pour lemon cream into glasses and chill for at least 2 hours. Afterwards you can enjoy the food.