Sour cream sponge cake

Sour cream sponge cake differs from the usual one in greater humidity, or something. As a rule, any biscuit prepared in the traditional way (flour, sugar, eggs) always remains dry and requires additional impregnation in the form of various syrups, juices or alcoholic beverages. Sponge cake with the addition of sour cream can not be soaked in anything – it will not be dry. However, the cream that you will use with it will play a role here. In principle, the ideal cream for such a cake is still sour cream - the food will eventually be more harmonious, or something. This recipe refers to the "general" kitchen. At least, I've known him for a long time.
We divide the sugar into two parts. The first part is rubbed with chicken yolks until the latter are completely whitened. Separately, beat the cooled proteins with sugar into a strong, stable white foam. We mix sour cream and flour into the yolks, then carefully add the proteins, but do not beat, but simply mix. Bake in an oiled form in the oven until ready. The oven must be warmed up. Keep in mind that at least fifteen minutes, when you put the cake in the oven, do not open the door. When the biscuit is browned, turn off the fire, open the door slightly and let the cake cool for ten minutes. Only then we take the mold out of the oven.