Filling

1. Combine all of the filling ingredients in a medium bowl. Set aside 1 tablespoon of the filling.

Dough

1. Grease a large bowl and set aside
2. Combine and whisk together the milk, egg yolks and vanilla extract.
3. Using a stand mixer fitted with the dough hook, mix the flour, sugar, yeast and salt on low speed until combined, about 30 seconds
4. Slowly pour in the milk mixture and mix until the dough comes together, about 3 minutes
5. Increase the speed to medium-low and add the butter, one piece at a time, until they have all been incorporated
6. Continue to mix until the dough is smooth and comes away from the sides of the bowl, 10 to 12 minutes
7. Transfer the dough to the prepared bowl, cover with plastic wrap, and let rise at room temperature until risen slightly, about 1 hour.
8. Place the bowl in the refrigerator until the dough is firm and has doubled in size, at least 1 hour.

Assemble the Babka

1. Punch down the dough on a lightly floured work surface
2. Roll out the dough to a 20 by 14-inch rectangle
3. Spread all but the 1 tablespoon reserved filling over the dough, leaving a ½-inch border around the edges
4. Working from the short side, roll the dough into a cylinder and pinch along the seam to seal
5. Place the dough seam side up and roll back and forth until stretched to 18 inches long
6. Spread the reserved filling over the top of the rolled out dough
7. Fold the dough in half pinch the ends to seal
8. Place the shaped dough seam side down into a buttered loaf pan, cover loosely with plastic wrap and let rise at room temperature until it doubles in size

Bake

1. While the dough is rising, preheat the oven to 350 degrees F
2. Sprinkle the top of the loaf with cinnamon sugar
3. Bake until the loaf is deep golden brown, about 45 minutes
4. Allow the bread to cool in the pan for 20 minutes, then remove the loaf from the pan and cool completely
5. Store in airtight container for up to three days or freeze