Separate eggs into whites and yolks. Beat the whites without sugar until soft peak, then in a few receptions to introduce 50 g of sugar and beat until stable peak. Set aside.
Add a pinch of salt and 10 sugar to the yolks, beat in a light and fluffy mass. In several steps, pour vegetable oil, beat with a mixer.
Then in several receptions into the milk, mix with a mixer. Pour the sifted flour, short punch mixer at low speed.
In a few steps, mix the whipped whites of the yolk-flour mixture by the method of "top-down", "from the edges-to the center."
Sponge dough is obtained pouring consistency, not thick.
Baking sheet size 40x30 cm. Bake a sponge on a baking sheet, covered with baking paper. in a preheated 170-180 C oven for about 20 minutes. Readiness is determined by a dry splinter or by gently pressing the finger in the center - the finger should not fall into the dough.
Slightly cooled sponge cover with a clean sheet of baking paper, a quick movement to turn, gently separate the paper.
Put the baking paper clean side to the biscuit, roll into a non-tight roll, cool completely.
Mix sour cream, chicken egg, vanilla sugar, sugar, flour (can be replaced with starch) until smooth.
Brew the cream with constant stirring: in a water bath or in a bowl with non-stick thick walls on low heat. Cool to room temperature.
Butter beat, continuing the process of whipping add portions of the custard base. The cream is thick in consistency.
Grease cooled sponge cream (if there is no time - just a thick jam with sourness), roll into a roll, trim the edges, decorate the top of the roll to your liking or sprinkle with powdered sugar.