Remove the eggs from the refrigerator in advance. It is important that the eggs for the cakes are not cold. The cake will be more fluffy. Sift the flour. Cool the cream in the refrigerator.
Prepare the dough. Break the eggs and place in a blender bowl. Beat with a pinch of salt for 3 minutes until fluffy. Without stopping whisking, gradually add condensed milk in a thin stream. Mix the prepared flour with baking powder, add to the mixture of eggs and condensed milk. Knead the dough.
Divide the resulting dough into two equal parts. Line a baking dish, preferably no larger than 40x40 cm, with parchment or a silicone mat and grease with butter. Place half of the dough in the prepared pan, spread into a thin, even layer and smooth its surface.
Place the pan with the dough in an oven preheated to 180°C and bake for 7 minutes until done. Bake the second cake in the same way. Remove cakes from parchment paper or silicone mat and cool on a wire rack. Divide the cooled cakes into 4 parts each.
For the cream, whip cold cream and add vanilla sugar. Add condensed milk to the whipped cream in a thin stream, continuing to beat with the mixer at medium speed.
Assemble the cake. Place a little cream on the bottom of the dish so that the cake does not move on its surface. Place the cakes one at a time, covering each cake with a layer of cream 2 cm thick. Grease the top and side surfaces of the cake generously with cream and level with a pastry spatula. Place the cake in the refrigerator.
Decorate the cake as you wish: fresh raspberries, blueberries, strawberries. When serving in portions, place triangular pieces of cake on a plate, lightly sprinkle it with cocoa powder, and garnish with fresh berries.