In microwave safe bowl add butter and milk and melt it by heating high for 30 seconds.

In the bowl of a stand mixer fitted with the paddle attachment, combine the warm milk –butter mixture, sugar, yeast, egg, flour, and salt, and mix on low speed until sticky dough begins to form. Switch to the dough hook, and knead on low speed for 10 minutes. (The dough will be loose and sticky, don't add any more flour . It will all come together as it rises.)

Butter a large bowl, and place the dough inside. Cover with plastic wrap or a tea towel and let it rise until doubled, about 1 ½ to 2 hours.

In the bowl of a food processor add the chocolate chips sugar, cinnamon, and salt, and pulse until chocolate is fairly finely chopped and some parts powdery. Add the butter, and pulse until the mixture comes together. Set aside.

Very generously butter a 12 cavity muffin tin.

Turn out the dough onto a lightly floured work surface, and gently deflate the dough. Let the dough rest for 5 minutes.

Roll the dough into a large rectangle, about 12x20-inches. Add flour if the dough is get sticking.

Sprinkle the filling evenly over the dough. Roll the dough into a tight log, starting from the short end and rolling to the other end. Pinch the seams. Using a serrated knife or tooth floss (the best!), cut the dough into about 1-inch segments. Place each segment into the prepared muffin tin.

(If you want to bake the next day, cover with plastic wrap and refrigerate the dough overnight. Bake as directed without letting the dough rise again. Otherwise the dough can also be covered and frozen at this point).

Cover with plastic wrap and let rise for about 30 minutes.

Preheat oven to 350 degrees F.

Whisk the egg and cream together, and brush the tops of the buns with the egg wash. and bake for about 30 minutes, until puffed and brown around the edges.

Let cool on a wire rack in the muffin tin. These are easier to remove from the muffin tin if completely cool. It is really hard to resist they are at prime when it is warm.

If you would like an ultra chocolatey bun, you can increase the filling by 50% and this would yield a bun to filling ratio similar to what is in the original babka recipe from Martha. /These buns are best eaten the day they are made, however they were still good the next day reheated for about 10-15 seconds in the microwave.