Because I took a recipe for three loaves and converted it into a recipe for one loaf, and the cups and spoons weren't nicely divisible by three, you'll probably want a scale for this.
Chocolate Babka
Adapted from Smitten Kitchen. Makes 1 loaf.
1/2 cup warm milk (110 degrees F)
4.666 grams active dry yeast (less than 1 packet)
116 grams cups, plus a pinch, sugar
1 large egg
1 egg yolk
2 cups all-purpose flour, plus more for work surface
1/4 tsp salt
1 1/6 stick butter, divided use, plus more for bowl and loaf pans
12 oz (1 bag chocolate chips) bittersweet chocolate
1 Tbs ground cinnamon
1 tsp heavy cream (or half&half, or whole milk)
1 recipe streusel topping (optional, see below for recipe)
Get eggs and butter out to warm up. Go for a walk. Come back, and begin:
Pour warm milk into a small bowl. Sprinkle yeast and pinch of sugar over milk and let stand five minutes.
In another small bowl, fork-whisk together 43.5 grams sugar, and 2/3 of one egg, beaten (reserve remaining 1/3 of egg for egg wash), and 1 egg yolk. Add egg mixture to yeast mixture, and whisk to combine.
In large mixer bowl, place flour and salt. Add egg mixture and stir with fork (that you used in previous step) until almost all the flour is incorporated. Add 5.333 tablespoons butter, and use dough hook to mix on low speed until butter is incorporated and you have a smooth dough (5-10 minutes).
Turn dough out onto a lightly floured surface and knead a few turns. Butter a large bowl, place dough in bowl, and cover tightly with plastic wrap. Set aside in a warm place to rise until at least doubled in bulk, about 1 hour. (This took a bit longer for me, my yeast may have been old.) While dough rises, make steusel topping (if using, recipe at end), and chocolate filling
Chocolate filling: Place chocolate chips, 65 grams sugar, and cinnamon in food processor and grind until chocolate is in smaller chunks. Then add 4 tablespoons (half a stick) of butter and mix until a homogenous but lumpy paste forms. Set aside in a cool place.
Butter bottom and sides of loaf pan, then line with a parchment paper strip which runs the length of the pan and up both short sides, sticking up at least 1/2 inch on each end. Add dash of cream to reserved beaten egg: this is your egg wash.
Punch down risen dough, and transfer back to well-floured surface. Roll out into a 14 x 18-inch rectangle.
With your hands, crumble all but 2 Tbs of the chocolate filling evenly over dough, leaving a 1/2-inch border. Brush edges with egg wash. Roll dough up tightly like a jelly roll along the long axis (the roll will be 13 inches long). Pinch roll ends together to seal, and press down on seam. Twist roll 5 or 6 turns by lifting up and twisting one end/half at a time. Brush top of roll with egg wash. Carefully crumble remaining chocolate filling over the left half of the roll, press it into dough. Fold right half of the roll over onto the coated left half. Pinch to seal the ends. Twist roll 2 turns and snuggle into prepared pan.
Loosely cover with plastic wrap and let stand in a warm place 20 to 30 minutes. Heat oven to 350. Brush the top of loaf with egg wash. Crumble streusel topping over loaf. Don't worry if some falls down around the dough, it will be fine.
Bake, rotating halfway through, until golden, about 45 minutes. Lower oven temperature to 325 degrees and bake until deep golden, 15 to 20 minutes more. Streusel topping may remain white, judge brownness by exposed dough on top. Remove from oven, and transfer to wire rack until pan is cool enough to touch. Remove from pan, slice and serve immediately for still-warm goodness. When fully cooled, keep the rest well wrapped at room temperature.
Steusel topping (optional)
1/4 cup confectioner's sugar
25 grams flour
1/4 stick butter
Combine ingredients with a fork or two knives or a pastry blender until you have variously-sized lumps (from crumbs to peas).
