Fantastic Kefir Chocolate Cake

In one bowl, lightly whisk together the eggs, vegetable oil, and kefir. In another bowl, mix the flour, sugar, baking soda, and cocoa powder.

Pour the wet ingredients into the bowl with the dry mixture and stir well until combined.

Pour the batter into a greased baking pan and bake for 50 minutes at 180–190 °C.

Slice the cooled cake horizontally into 3 layers and fill/frost with your choice of cream.

For the sour cream frosting: combine softened butter with sour cream and sugar, then whip.

For the custard: bring the milk to a boil; whisk the eggs with the sugar, gradually beating in the flour. Pour the mixture in a thin stream into the boiling milk while stirring, add vanilla, let cool, and combine with softened butter.