Cold butter grate and mix with egg mass, vegetable oil, sour cream and soda.
Add the flour to the liquid mass.
Knead a homogeneous dough, put it in a bag and put it in the refrigerator for 30 minutes.
Turn on the oven to warm up. mix the jam with the starch.
Get the dough, divide into 2/3 and 1/3. Most of the roll out in a circle, 34 cm, 1 cm thick..
The form is greased with oil, sprinkle with flour or cover with baking paper. Transfer the dough to the mold, forming the sides. Lay out the jam.
Decorate the blank with the remaining dough. Bake at 180-190 degrees for 35-40 minutes.
Carefully remove from the mold, cool. When serving, decorate with a “snowball” of powdered sugar.