Mousse:
Soak the gelatin in cold water.
Put water in a saucepan and add sugar, and let it boil for 3 minutes.
Whip the egg whites.
Add the soaked, squeezed gelatin to the boiling sugar mixture and stir until dissolved. Pour in a fine stream into the whipped egg whites and continue whipping until it is firm and cold.
Put the strawberries and lemon in the blender and mix into a coulis, reserve 300 ml.
Gradually mix this into the mascarpone.
Fold in the whipped egg whites.
Biscuit:
Separate the eggs and whip the egg whites with the sugar until stiff. First mix in the yolks and then the sifted flour.
Put in a piping bag and pipe long lines onto a baking sheet lined with parchment paper, leaving a narrow space of 1-2 mm between each line, sift icing sugar over it.
Pipe a round circle of dough for the bottom of the baking pan (diameter 20 cm) and sift icing sugar over this as well.
Bake for 5’ in a preheated oven at 230°.
To check if it is baked enough, you can press down on the dough. If it leaves a dent, it is not baked enough; if the dough springs back, it is okay.
Let cool.