Chocolate cake

Directions:

Warm the milk and melt 1/4 cup butter in a glass or ceramic bowl in the microwave for 30 seconds, or on the stovetop in a saucepan. Combine the bread flour, 2 cups all-purpose flour, yeast, and 1/4 cup sugar. Add the water, the milk-butter mixture, the egg, and the salt to the dry ingredients and mix well.
Use the dough hook in a stand mixer on low speed or knead the dough by hand until the dough is smooth and elastic, about 15 minutes. If the dough is too wet, add more bread flour, about 2 tablespoonfuls at a time (up to 8 tablespoons) to make a workable dough; too much flour can make the dough dry. Cover the dough with a damp cloth and let rise until double in size, about 1 to 1 1/2 hours.
Make the chocolate filling and the streusel while the dough is rising. For the filling, stir together the finely chopped chocolate, the cinnamon, and 1/4 cup sugar. Cut in 1/4 cup chilled butter with a fork. To make the streusel, combine the confectioners’ sugar and 1/4 cup all-purpose flour; cut in 1/4 cup chilled butter until the mixture resembles coarse crumbs.
When the dough has doubled, punch the dough down and cut it into two equal pieces. Loosely shape each piece into a ball. Cover the dough with a damp cloth and let it rest for 10 minutes.