Make the base: mix sugar with cornstarch and salt. Beat the whites until stiff peaks form, gradually adding the sugar mixture.
Then add the vinegar and beat for another 1 minute on the lowest speed of the mixer.
Place parchment or a silicone mat on a baking sheet. Visually divide the baking sheet into 3 cakes with a diameter of 20 centimeters.
Form 3 cakes from the whipped egg whites, carefully leveling their surface.
Place the baking tray with the preparations in the oven and reduce the temperature to 130°C. Bake for 30 minutes. Then reduce the temperature to 100°C and bake for another 60 minutes.
Prepare the filling: whip the cream with sugar until stiff peaks form. You can add a little food coloring for color.
Assemble the cake: put a layer of cream on the bottom layer, sprinkle with blueberries and almond flakes, cover with the second layer and repeat the procedure with cream, blueberries and almond flakes.
Place the third cake layer, cover it with the remaining cream, add berry jam, blueberries and serve.