Mix the sifted flour, baking powder, sugar and salt..

Chilled butter chopped with a knife and mix with flour ground into crumbs. Then add the yolk and knead a soft dough. Remove the prepared dough in the cold for 20-30min.

Sour cream mixed with sugar and vanilla. Cook over medium heat, stirring occasionally, until mixture begins to thicken. Approximately, 15 minutes. The darker the density, the thicker will be the cream after cooling.

Divide the dough into two parts. One part should be about three to four times less. Roll out a big part in Plast ~1-1.5 cm, Distribute the cream over the entire surface. Remaining dough grind into crumbs, add cereal and chopped nuts, put on top of the cream. Bake at 180-200 grams.25-30 minutes. The baking time and the mode depends on the oven.