Chocolate-Cinnamon Babka

Ingredients

• warm milk

  110 degrees
  1 1/2 cups
• (1/4 ounce each) packages active dry yeast
  2 unit
• plus a pinch of sugar
  1 3/4 cups
• large eggs

  room temperature
  3 whole
• egg yolks

  room temperature
  2 large
• all-purpose flour

  plus more for work surface
  6 cups
• salt
  1 teaspoon
• (3 1/2 sticks) unsalted butter

  cut into 1-inch pieces, room temperature, plus more for bowl and loaf pans
  1 3/4 cups
• semisweet chocolate

  very finely chopped*
  2 1/4 pounds
• After chopping the chocolate into moderately sized chunks

  I used the food processor to pulse the rest of the chocolate in two batches to small bits. It saved a lot of time!
  1 unit
• ground cinnamon
  2 1/2 tablespoons
• heavy cream
  1 tablespoon
• Streusel topping (see below)
  1 unit