Add warm milk (200 ml) to the bowl, add yeast (7 gr.). Take 2 tablespoons of the total flour and add to the milk - yeast mixture. Then take 1 tablespoon of the total sugar and add it to the milk - yeast mixture. Mix until well blended. Put the mixture in a warm place to dissolve the yeast.
As soon as the milk-yeast mixture increases in size and a cap of small bubbles is formed on the surface, add 1 tablespoon of cognac to the mixture, add 1/2 teaspoon of vanilla essence, add 3 egg yolks. Beat the mixture well with a fork.
Then add the melted butter at room temperature (70 g), sour cream (2 tablespoons), add 1/2 teaspoon of salt, vegetable oil (1 tablespoon) and the remaining sugar. Mix the mixture well.
Then add the rest of the flour. Flour may need a little more than 3.5 cups or a little less. It all depends on the quality and humidity of the flour. Flour is different.
Knead dough. The container with the dough is covered with food wrap and put in a warm place to rise. After the first rise, knead the dough and put it to rise again. Then put the dough in the refrigerator for about 30-40 minutes. You can stay for an hour.
Then you can start cutting the buns. From the total amount of dough you will get about 12-14 PCs., everything will depend on the size of the buns. Roll out the dough into a layer, grease the layer with melted butter using a cooking brush, sprinkle the surface with nut crumbs. Then lightly roll the nut layer with a rolling pin, slightly pressing the nut crumbs.
Roll the layer into a roll. Grease the edge of the dough with water and lightly fasten it. Then turn the seam down.
Cut on a trapezoid.
Place the rolls on a baking sheet covered with parchment and allow to stand for about 10-15 minutes. Then, using a cooking spatula or other suitable tool, slightly press down the center. Grease the buns with beaten egg. Send the baking tray with rolls to the oven preheated to 180-190C.