Chocolate Cake with Sour Cream and Condensed Milk Frosting

Beat the eggs for 2 minutes, add the sugar, and whip until light and pale.

Mix the kefir with the baking soda, pour it into the egg mixture, and stir well.

Add the vegetable oil and beat again.

Sift the cocoa powder and flour together, fold them into the batter, and mix until smooth.

Line a baking pan with parchment paper and pour in the batter. Bake at 350 °F (180 °C) for about 40 minutes—check for doneness with a skewer.

Let the finished sponge cake cool completely.

Combine the sour cream and condensed milk, and whip until fluffy.

Cut the sponge cake into 2–3 layers, spread the frosting between them, and decorate as desired—drizzling with melted chocolate works great.