Grease a baking tin with margarine or butter and dust with a little flour, put in the refrigerator.
Separate the eggs. Beat half of the sugar with egg whites to make snow. Beat the egg yolks with the other half of the sugar and hot water until frothy. Preheat the oven to 150 ° C.
Sieve the flour, baking powder and cocoa powder onto the egg-sugar mixture, then pour the egg whites on top. Fold in everything with a large whisk. Fill the baking pan with the mixture and bake in the preheated oven at 150 ° C for 30 minutes, then turn it out onto a rack and let it cool down.
Wash the strawberries, remove the stems and cut into small pieces as desired. Squeeze the lemon. Cover the cake base with the strawberries and prepare the icing with the lemon juice and water (and possibly 2 tablespoons of sugar) according to the instructions on the packet and pour over the strawberries.