Yeasted Chocolate Coffee Cake

Yields 1 loaf
Dough
2 1/4 teaspoons active dry yeast
1/4 cup plus a pinch of granulated sugar
3/4 cup warm milk, about 110° F (43° C)
1 large egg plus 1 large egg yolk
3 cups all-purpose flour
1 stick salted butter, room temperature

In a large bowl of a stand mixer, sprinkle the yeast and a pinch of granulated sugar over the warm milk. Let stand for 5 minutes, or until foamy.

In a small bowl, whisk together the remaining sugar, the whole egg, and the egg yolk. Stir into the yeast mixture. Add the flour and salt and mix until combined. Switch to the dough hook attachment. Add the salted butter and mix until the dough is soft and sticky, about 10 minutes.

Place the dough onto a lightly floured work surface and knead until smooth. Place the dough into a greased bowl and cover with plastic wrap or a clean kitchen towel. Let rise in a warm place until doubled in volume, 1 to 1 1/2 hours.

Filling
8 ounces bittersweet chocolate, coarsely chopped
1/2 cup brown sugar
2 teaspoons ground cinnamon
4 tablespoons unsalted butter, room temperature
1 large egg, lightly beaten with 1 tablespoon heavy cream, for egg wash

In a small bowl, mix together the chocolate, brown sugar, and a cinnamon. Using a pastry blender, cut in the butter until the mixture is uniform. Reserve 1/2 cup for later use.

Punch down the dough. On a lightly floured surface, roll out the dough until it is an 18-inch square. Brush the egg wash around the edge of the dough to make a 1-inch border. Spread the chocolate mixture (minus the 1/2 cup) evenly throughout the dough, leaving the border clean. Starting at one end, roll the dough tightly like a jelly roll. Pinch the edges closed. Fold the dough in half and twist 2-3 times. Place the dough into a greased loaf pan. Brush the top of the dough with egg wash and sprinkle the remaining 1/2 cup of filling over the top of the dough. Cover the dough with plastic wrap and allow the dough to double in size, 20-30 minutes.

Preheat the oven to 350 degrees F.

Bake the loaf for 55 minutes, or until the top is deeply golden. Transfer loaf to a cooling rack and allow to cool completely. Enjoy!