Summer Cake

Bake the sponge cake. To do this, mix baking soda into a glass of sour cream and stir.

Beat the egg with sugar.

Add the sour cream and beat.

Sift in the flour and mix. The batter will be quite runny.

Bake the sponge in a 16 cm ring or pan for about 30-40 minutes. Check for doneness with a toothpick—it should come out clean from the center.

Let the sponge cool completely.

Wash and dry the berries.

Trim the top ("dome") of the sponge cake and scoop out the crumb to form a "bowl" from the base. Also scoop out the crumb from the trimmed top, and grate all the extracted crumb into fine bits (I use a coarse grater).

Make the frosting by whipping chilled sour cream with powdered sugar at high speed with a mixer until it increases in volume by about 1.5 to 2 times. The cream should be very fluffy.

Mix the crumb with half of the prepared frosting.

Add some berries (to taste) and gently fold everything together.

Fill the sponge "bowl" with the mixture and press down firmly.

Top with the remaining sour cream frosting.