In the bowl of your mixer, stir yeast and water together. Let sit 5 minutes.
Add the flour, butter, sour cream/yogurt, eggs salt and vanilla and stir until smooth.
Cover with a damp cloth and put in the fridge for at least 2 hours, up to 2 days.
The dough will look basically unchanged at this point.
Preheat the oven to 375F.
Combine the sugar and cinnamon.
Roll dough into a 15×18 inch rectangle, then spread the cinnamon sugar mixture on top of it.
Fold the dough like a letter towards the middle into thirds.
Then turn the dough horizontally and roll into a ¼ inch rectangle.
Then slice into 1 inch strips.
Grease or cover two baking sheets with parchment paper.
Twist the strips by picking up each end of the strip and twist in opposite directions.
Then place on the tray next to the others.
Bake for 15 minutes and then devour!