In the bowl of an electric mixer using the paddle attachment on low speed, blend together the warm milk and sugar.

On low speed, add the egg yolks and the vanilla and blend well.

In a medium mixing bowl, whisk together 2 cups of the flour, the salt and yeast until well combined.

Add the flour mixture to the milk mixture and blend well on low speed.

Stop the machine and, using a rubber spatula, scrape down the sides of the bowl.

Change to the hook attachment and add the remaining 2 2/3 cups of flour, stopping the machine periodically to incorporate the dry bits of flour back into the dough. Using your hands works best for this.

Knead the sticky dough by increasing the mixer speed to medium high for 2 minutes.

On low speed, add the softened butter in several small additions waiting for the dough to absorb the butter before adding anymore.

Using a bowl scraper, transfer the dough to a floured work surface.

Knead the dough with the help of a dough scraper until most of the butter has been incorporated. Continue kneading for another 3-4 minutes.

Grease a large bowl and place the dough in the bowl flipping it over so the greased side is up. Cover the bowl with plastic wrap and allow it to rise in a warm place for 1-2 hours or until almost doubled in size.

In a small saucepan, bring the cream to a boil over high heat. Remove the pan from the heat and add the chocolate chips all at once.

Whisk the mixture until the chocolate melts and the filling is smooth.

Pour chocolate filling into a medium bowl and allow it to get to a spreadable consistency at room temperature for a few hours or in the refrigerator for 30 minutes or so.

In a separate small bowl, blend together the brown sugar and cinnamon with your fingers.

Spray two 9 by 5 by 3 inch loaf pans with non-stick cooking spray. Line the bottoms with a strip of parchment paper so that the parchment hangs over the two longer sides of the pan by approximately 2 inches. Secure with oven proof clips if desired.

Spray the parchment paper with non-stick cooking spray.

Place the dough onto a work surface, and using a dough cutter, divide the dough in half. Place half of the dough back in the bowl and set it aside.

Using a rolling pin on a lightly floured work surface, roll out one half of the dough into a 14 by 15 inch rectangle.

Using an offset spatula, spread half of the chocolate filling evenly over the dough.

Sprinkle half of the brown sugar and cinnamon mixture evenly over the chocolate filling. Gently press sugar in with your hands.

Tightly roll up the dough as if you are rolling up a towel into a tight spiral or log pinching the seams together.

Using a dough cutter, cut the log in half, crosswise, to create 2 logs.

To prevent the logs from becoming too soft, place the halved spirals onto a well greased sheet pan. Chill for up to 10-15 minutes.

Remove from the refrigerator and cut each log lengthwise in half, being careful to keep the cut sides facing up.

You should now have 4 open logs.

Watching this video, create a 4 strand braid tucking each end under itself.

Gently fit the braid into one of the prepared pans.

Repeat steps 4-13 with the remaining half of the dough.

In a medium bowl, gently combine the streusel ingredients with your fingers to create little clumps.

Scatter half of the streusel topping over each babka.

Place a piece of plastic wrap or a clean kitchen towel over each babka and allow them to rise for approximately 1 hour.

Preheat oven to 350° Fahrenheit.

Uncover babkas and bake for approximately 45- 50 minutes or until the loaves are brown and firm. If the loaves get too brown, cover them with a tent of aluminum foil.

Cool babkas for 15 minutes before gently turning them out to cool completely.