Chocolate Babka

0 Warm the  milk until it is 110F.
1 Put the milk into a large bowl and whisk in the yeast.
2 Whisk in 1 cup of the flour.
3 Set aside for 20 minutes. It will foam up.
4 Beat the butter and sugar in the mixer for 4 minutes on medium speed.
5 Add the eggs, yolk, and vanilla.
6 Continue to mix on medium speed - scrape down the sides often.
7 Add the remaining flour.
8 Now, add the milk mixture.
9 Mix on low speed with the dough hook until the dough pulls away from the bowl.
10 Oil the top with a light vegetable oil or butter.
11 Cover and refrigerate overnight.
12 The next day let the dough come to room temperature.
13 Separate it into two equal balls.
14 On a floured surface roll each ball of dough into a 12"x 20" rectangle.
15 Spread with the chocolate.
16 Cover with chopped chocolate.
17 Start rolling up from the long side, keeping it tight as you go.
18 Once it is rolled up fold it over so that it creates a "U".
19 Twist it a few times and put it in a well greased bread pan.
20 Brush with butter and sprinkle with streusel.
21 Let rise until the loaves are about 1 inch over the top of the pans.
22 Bake at 325F for 1 1/2 hours.
23 Cool completely.
24 Slice in thick slices.
Chocolate Filling
27 Whisk dry ingredients together in a medium bowl.
28 Combine cream and butter in a heavy pan and bring to a simmer.
29 Pour the cream mixture over he dry ingredients.
30 Mix well.
31 Add half the chopped chocolate to the mixture and stir until thick.
32 Set the rest of the chocolate aside.
33 As the mixture cools it will be like ganache.
Streusel
36 Chill the butter thoroghly and cut in one inch squares.
37 Combine all dry ingredients in a medium bowl.
38 Add the butter with your hands or a pastry cutter until it is the size of small peas/
39 Chill until ready to use.