Whisk the milk and flour together in a medium bowl until smooth. Microwave on high power for 30 seconds. Remove bowl and whisk vigorously. Return to microwave and heat for another 30 seconds. It should thicken to a stiff paste. Whisk until smooth. If mixture isn’t thick, heat in 15 second increments, whisking after each cycle, until thick paste forms.

Whisk 2/3 cup milk into the thick flour paste until smooth. Pour into the bowl of a stand mixer.

Using a dough hook, add the egg and egg yolk, then slowly add the yeast and flour. Mix until flour is incorporated, and the mixture turns into a mass of dough.

Stop the mixer and allow the dough to rest for 15 minutes.

With the mixer speed on medium and, using the dough hook, add sugar and salt to the dough. Knead for 5 minutes. Add butter and continue to knead an additional 5 minutes, scraping down the bowl as necessary. (Dough will be sticky.)

Cover the dough with plastic wrap. Allow to rise at room temperature until doubled in size, about 1 hour.

While the dough rises, whisk all the ingredients together until combined. Pour into the bottom of a greased 13 x 9-inch or you can use a 12-inch round metal baking pan. Spread the topping to the edges and set aside.

About 30 minutes before dough is done rising, melt the bittersweet chocolate and butter. You can use a double-boiler or microwave at 50 percent power in 30 second increments, stirring after each until melted. Refrigerate 30 minutes until firm.

Place the dough on a lightly floured surface and sprinkle top of dough with a light dusting of flour. Roll dough to form an 18 x 15-inch rectangle. The long side should be parallel to the edge of the counter.

Stir the bittersweet chocolate mixture until it resembles frosting. Spread over surface of dough rectangle, leaving a 1-inch border at the top edge. Sprinkle chocolate filling with chocolate chips.

Starting with the long end nearest the counter’s edge, loosely roll the dough into a log, toward the unfrosted edge. Use your hands to push in ends to create an even thickness as necessary.

Place the log seam side down and slice into 12 rolls. Place, cut side down, into the coated pan. Cover with plastic wrap and allow to rise until rolls are puffy, about 1 hour. The rolls should be touching after rising.

Heat oven to 375 degrees (F).

Remove plastic wrap and bake rolls on the middle rack for about 20 minutes. You may want to place a baking sheet on the lowest rack of the oven to catch any drips from the chocolate rolls as they bake.

Once the rolls are golden brown, cover loosely with foil and bake an additional 10–15 minutes longer, until rolls reach at least 200 degrees at the center of the bread.

Remove baking dish from oven, discarding foil. Run a knife along the edges of the pan. Place a large serving platter over the baking pan and carefully invert pan and platter. Remove pan and allow rolls to cool 15 minutes before serving.

While these rolls take about 4 hours to make, a lot of the time is hands off, waiting for the rolls to rise.

Be sure to use a metal baking pan, not glass or ceramic.