Dissolve the yeast in the lukewarm water with 1 teaspoon of sugar and 1 teaspoon of flour.

leave for 10 minutes, until it froths.

Combine the rest of the dough ingredients.

Beat the rest of the sugar with the egg and the yolk. Add the sour cream or oil, the salt, vanilla, and yeast mixture, and beat very well. Fold in the flour gradually, and continue beating until you have a soft, smooth, and elastic dough, adding more flour if necessary. Then knead for 5 minutes, sprinkling with a little flour if it is too sticky. Coat the dough with oil by pouring a drop in the bowl and turning the dough in it. Cover the bowl with plastic wrap and leave in a warm place to rise for about 1 hour, or until doubled in bulk.

Punch down, knead for a minute and cut to small ball.

Cut wax paper to squares, place each ball on a square and let rise again for 45 minutes.

Heat oil to 345F .

Holding a ball on the paper, turn into the hot oil and cover immediately.

After 2.5 minutes, tap with a wooden spoon, the ball will turn to the other side. Continue to cook uncovered for another 2 minutes.

Pick up with a slotted spoon on to a plate with a paper towel.

Inject with a small amount of jam and sprinkle with powder sugar.