Beat the egg whites and a pinch of salt with a mixer at medium speed, then add vanilla, albumin, lemon juice and gradually, beating the dough with a mixer, add powdered sugar and cornstarch.
Prepare a baking tray, cover it with parchment paper, sprinkle with almond petals, then using a silicone or wooden spatula, pour the protein dough onto the baking tray. Bake it for 25 minutes at 150 ℃.
Prepare the cream by combining mascarpone cheese, cream and 50 grams of powdered sugar in one container.
Remove the cake from the oven, wait until it cools, then spread it with cream, sprinkle with chopped fruit, roll the cake into a roll and leave it in the refrigerator for 2 hours to soak.