Beat the egg with salt to a light froth, then continue to beat until a fluffy mass is formed, gradually adding sugar.
Add the melted butter to the beaten egg mass and mix gently.
In the egg-butter mixture in 2-3 stages, sift the flour mixed with baking powder and cocoa powder, alternately alternating with hot milk. You may need less or more flour. The dough should be smooth, uniform and not very thick.
Put the dough in a split form (diameter 20 cm), lined with parchment paper, level.
Bake for about 10-12 minutes in a preheated 180 degree oven. Readiness can be checked with a wooden skewer. Attention! The baking time depends on the characteristics of the oven.
Wash the strawberries, dry them, and cut off the sepals. Part of berries cut in half, part of leave whole.
Ready to cool the sponge cake and put it in a split ring, the sides of which are previously lined with film. On the sponge cake in a circle, put the strawberry halves cut to the sides of the form, and in the middle - whole berries.
Pour the instant gelatin with hot milk, mix thoroughly and cool (or cook as indicated on the gelatin package).
In a deep bowl, mix the soft cottage cheese, yogurt, sour cream, powdered sugar and vanilla sugar.
Add a little curd mass to the cooled gelatin, mix and pour back into the curd mass.
Melt the chocolate in a water bath, cool, add to the curd mass.
Beat with a mixer for about 2-3 minutes.
Put the curd mousse on the berries, smooth them out and put them in the refrigerator for at least 2-3 hours
Remove the finished cake from the mold and decorate as desired.