Preheat oven to 350°F.
Dissolve yeast with sugar and vailla sugar in warm milk. Put aside for 5 minutes.
In a separate bowl combine eggs with sour cream with a fork. Add in yeast mixture.
Shred cold butter.
In a large mixing bowl, combine flour, shredded butter and mix until blended together. Add in yeast mixture and mix on medium speed until well combined.
Remove from mixer and knead briefly to form a large ball.
Divide into 7-8 even-sized balls. If making 8 balls, the finished kiflice will be smaller in size.
Keep dough in fridge until ready to roll.
Roll each to an 8 inch circle. Cut each circle into 8 triangluar slices (like a pizza).
Add 1-2 tsps of filling to the wide edge of the triangle (as much as will stay in when the pastry is rolled).
Turn the corners in a little bit (helps to keep the filling from draining out).
Starting on the wide side of the triangle, roll each triangle to form small crescent shapes.
Arrange onto ungreased cookie sheet or parchment paper about 1” apart.
Bake at 355°F for 14-16 minutes, until slightly golden.
Dip in a small bowl of sugar (mix of granulated and vanilla sugar) while still warm.