Instructions

1. 1
   Mix together milk, yeast, and 1 tsp sugar, then set aside. Ensure it does not clump.
2. 2
   Using a pastry knife, mix flour, butter, salt in a bowl until crumbly.
3. 3
   Add 3½ tbsp sugar and baking powder to the flour mixture.
4. 4
   In a separate bowl, whisk the egg yolks. Add the yeast mixture, then the sour cream and vanilla.
5. 5
   Mix the wet ingredients with the dry ingredients. You should get a dough with the consistency of peanut butter cookie dough. Add additional flour if the dough is too sticky.
6. 6
   Knead dough well and let stand 2 hours in a warm place. To allow the dough to rise, place the bowl with the dough (covered with a tea towel) onto the top rack of the oven and place a bowl of hot water on the lower rack. Leave the oven off, and this setup will gently warm and allow the dough to rise.
7. 7
   Divide the dough into 5 equally-sized balls.
8. 8
   Sprinkle sugar on a board, put a dough ball on the board, and roll out into a circle about 12 inches across.
9. 9
   Flip the dough over and put more sugar on the board. Cut like a pizza into wedges about 1½ inches at the widest. Put about 1 tsp filling on each wedge and roll in sugar.
10. 10
    Bake on a cookie sheet at 325°F for 15 minutes or until golden brown.