Chocolate Banana Bread Babka

1. Make the Dough: In a small pot, heat the milk over medium heat until it is just warm to the touch, about 2 minutes. Check the temperature with a thermometer; it should be around 95°F. If needed, let it cool before proceeding.

2. In the bowl of an electric mixer fitted with the dough hook attachment, mix the all-purpose flour, whole-wheat flour, brown sugar, yeast, salt and cinnamon on low speed to combine.

3. Add the warm milk, mashed bananas and eggs; mix on low speed for 3 minutes. Increase the speed to medium and mix for 2 minutes more. Transfer the dough to a lightly greased bowl, cover with plastic wrap and let rise in a warm place for 1 hour. It may not double in size, but it will look noticeably puffy.

4. Meanwhile, Make the Filling: In a medium pot, combine the heavy cream, butter, brown sugar, chocolate and vanilla extract. Heat over medium-low heat, stirring constantly, until the chocolate and butter are melted and the sugar is dissolved, about 3 minutes. Transfer to a medium bowl and let cool to a spreadable consistency.

5. Make the Streusel: In a medium bowl, whisk together the flour, brown sugar, cocoa powder and salt. Add the melted butter and stir with a silicone spatula until the mixture forms moist crumbs. Gently stir in the banana pieces.

6. When the dough has risen, lightly grease a 9-by-5-inch loaf pan with nonstick spray. On a lightly floured surface, roll out the dough into a rectangle about 14 by 18 inches.

7. Dollop the filling all over the dough and then use an offset spatula to spread it into an even layer across the dough, all the way to the edges. Sprinkle three-quarters of the streusel evenly over the filling.

8. Starting on one of the shorter sides, roll the dough into a tight spiraled log. Use a bench scraper or a knife to cut the log in half lengthwise. Twist the two halves together (this can get a bit messy, but never fear!) and then transfer to the prepared loaf pan.

9. Sprinkle the remaining streusel over the loaf. Cover with plastic wrap and let rise in a warm place until it looks noticeably puffy, 35 to 45 minutes.

10. Toward the end of the rise time, preheat the oven to 350°F. Bake the loaf until it is browned on the surface and appears fully set all the way through. (The best way to tell is to take an internal temperature; it should be around 200°F.)

11. Let the loaf cool inside the pan for 20 minutes, then unmold onto a wire rack and cool completely before slicing and serving.