Gluten Free Chocolate Babka
3 cups (420 g) Gluten Free Bread Flour, plus more for sprinkling
1/4 teaspoon cream of tartar
1 teaspoon (3 g) instant yeast
1/4 cup (50 g) granulated sugar
1/2 teaspoon (3 g) kosher salt
2/3 cup (5 1/3 fluid ounces) warm milk (about 95°F)
2 eggs (100 g, weighed out of shell) at room temperature, beaten
4 tablespoons (56 g) unsalted butter, melted and cooled
1/4 cup Homemade Fudge Sauce, at room temperature
Egg wash, for brushing (1 egg + 1 tablespoon water, beaten well)
Make the bread dough. In the bowl of your stand mixer, place the flour, cream of tartar, instant yeast and sugar, and use a handheld whisk to combine well. Add the salt and whisk to combine well. Add the milk, eggs and butter, and mix on low speed with the dough hook until combined. Raise the mixer speed to medium and knead for about 5 minutes. The dough is a lovely, smooth, enriched dough. It climbs up the dough hook during kneading but remains intact and smooth. Spray a silicone spatula lightly with cooking oil spray, and scrape down the sides of the bowl. Transfer the dough to a lightly oiled bowl or proofing bucket large enough for the dough to rise to nearly double its size, spray the top of the dough with cooking oil spray, and cover with an oiled piece of plastic wrap (or the oiled top to your proofing bucket). Set the covered dough to rise in a warm, draft-free environment until nearly doubled in size (about 1 hour). Once it has risen, place it in the refrigerator for at least 15 minutes or until it is chilled. This will make it much easier to handle.
Preparing the dough for shaping. Once the dough has risen and chilled, line a small rimmed baking sheet with unbleached parchment paper, and set it aside. Turn out the chilled dough onto a lightly floured surface and, using the scrape and fold kneading method and using a very light touch, sprinkle the dough with more flour and knead it lightly, sprinkling with flour when necessary to prevent it from sticking, scrape the dough off the floured surface with a floured bench scraper, then fold it over on itself. Repeat scraping and folding until the dough has become smoother. Do not overwork the dough or you will incorporate too much flour and it will not rise properly.
Rolling out and filling the dough. On a lightly floured surface, roll out the dough into a rectangle about 1/4-inch thick, and 10-inches high x 12-inches wide, sprinkling very lightly with more bread flour as necessary to prevent sticking. As you work, shift and move the dough frequently, as shown in my pizza shaping video. Before the dough is fully shaped, transfer it to a piece of unbleached parchment paper. Spread the fudge sauce in an even layer on the dough, leaving a 3/4-inch border clean around the perimeter. Beginning at a 12-inch side of the dough, and using the parchment paper to assist you, roll the filled dough tightly into a cylinder, like a jelly roll, ending with the seam side down. Cover the dough loosely with plastic wrap, and place in the refrigerator to chill for about 10 minutes. This will make the final shaping easier.
Final shaping and rise. Grease or line a standard loaf pan with unbleached parchment paper and set it aside. Once the dough has finished chilling, remove it from the refrigerator and uncover it. With a very sharp knife or pizza wheel, beginning about 1-inch from one end of the roll of dough, slice along the length of the dough all the way through to the end. You will have 2 strands of layered dough. Beginning at the intact end, twist each strand gently so that the cut sides of the dough are facing up. Braid the strands gently but securely back and forth over one another until you reach the end. You should have 4 twists before you reach the end. Cinch the open ends together and tuck them under the bread slightly. Place one hand on each end of the braid, and press the ends gently toward one another to create a slightly wider, shorter braid. Invert the braid onto a piece of parchment paper on top of a cutting board, then invert the prepared loaf pan over the top of the bread dough, covering the braided dough completely. Quickly re-invert the whole operation—from the loaf pan all the way down to the cutting board—and remove the cutting board and top parchment paper. Cover the dough with a piece of oiled plastic wrap, and place in warm, draft-free location to rise only until just beginning to swell (about 20 minutes, but it could be more if your rising environment is particularly cold and/or dry). Do not overproof.
Bake. As the dough is in its final rise, preheat your oven to 375°F. Once the dough has finished rising, uncover it, brush the surface evenly with the egg wash, and place in the center of the preheated oven. Bake for 10 minutes, and turn the oven temperature down to 350°F. Continue to bake until the dough is golden brown all over and the bread seems mostly firm to the touch (about 25 minutes more). Remove from the oven, place the loaf pan on a wire rack and allow to cool for about 10 minutes before removing from the loaf pan, slicing and serving.