Chocolate Babka

Why this recipe works If you don’t live within driving distance of New York City, it’s hard to get your hands on really great babka. For that reason, we decided to devise a foolproof recipe to use in our own Boston kitchens. While cinnamon filling is also a common choice for babka, we wanted to make a decadent chocolate babka, with a deep, dark filling. By definition, babka is a rich, tender dough, akin to brioche. But go too far in that direction and the dough will collapse under the weight of the filling, leaving large holes in the bread. To add richness yet preserve the loaf’s structural integrity, we cut back on the butter found in most traditional recipes and substituted two egg yolks for one whole egg. Chilling the dough after rising ensured that it was firm and pliable enough to fill and twist into its signature shape. For the filling, we used a combination of bittersweet chocolate and cocoa powder, which provided the full, rounded chocolate flavor and appealingly fudgy texture we were looking for. To make sure that the filling stayed put and didn’t sink to the bottom of the loaf, we also mixed in confectioners’ sugar and an egg white, which helped stiffen it up. The test kitchen’s preferred loaf pan measures 8½ by 4½ inches; if you use a 9 by 5-inch loaf pan, increase the shaped rising time by 20 to 30 minutes and start checking for doneness 10 minutes earlier than advised in the recipe. We do not recommend mixing this dough by hand. If the dough becomes too soft to work with at any point, refrigerate it until it’s firm enough to easily handle.

MAKES: 1 loaf

RISING TIME: 3 to 4 hours

RESTING TIME: 1 hour

BAKING TIME: 40 minutes

TOTAL TIME: 5 to 6 hours, plus 3 hours cooling time

KEY EQUIPMENT: stand mixer, 8½ by 4½-inch loaf pan, rolling pin, pastry brush, instant-read thermometer

INGREDIENTS:

FOR THE DOUGH

• 2 cups (10 ounces) all-purpose flour
• 1½ teaspoons instant or rapid-rise yeast
• ½ teaspoon salt
• ½ cup (4 ounces) whole milk, room temperature
• ¼ cup (1¾ ounces) granulated sugar
• 2 large egg yolks, room temperature
• 1 teaspoon vanilla extract
• 8 tablespoons (4 ounces) unsalted butter, softened

FOR THE FILLING

• 2 ounces bittersweet chocolate, chopped
• 4 tablespoons (2 ounces) unsalted butter
• 3 tablespoons unsweetened cocoa powder
• ¼ cup (1 ounce) confectioners’ sugar
• 1 large egg white
• 1 large egg, lightly beaten with 1 tablespoon water and pinch salt

INSTRUCTIONS:

1. For the dough:
   • Whisk flour, yeast, and salt together in the bowl of a stand mixer.
   • Whisk milk, sugar, egg yolks, and vanilla in a 4-cup liquid measuring cup until the sugar has dissolved.
   • Using the dough hook on low speed, slowly add the milk mixture to the flour mixture and mix until a cohesive dough starts to form and no dry flour remains, about 2 minutes, scraping down the bowl as needed.
2. Increase the speed to medium-low, add butter, 1 tablespoon at a time, and knead until the butter is fully incorporated, about 4 minutes.
   • Continue to knead until the dough is smooth and elastic and clears the sides of the bowl, for 10 to 12 minutes.
3. Transfer the dough to a lightly floured counter and knead by hand to form a smooth, round ball, about 30 seconds.
   • Place the dough seam side down in a lightly greased large bowl or container, cover tightly with plastic wrap, and let it rise until increased in size by about half, for 1½ to 2 hours.
   • Place the dough in the refrigerator until it is firm, for at least 1 hour or up to 24 hours. If the dough is chilled longer than 1 hour, let it rest at room temperature for 15 minutes before rolling out in step 5.
4. For the filling:
   • Microwave chocolate, butter, and cocoa together in a medium bowl at 50 percent power, stirring occasionally, until melted, for about 30 seconds.
   • Stir in sugar until combined and let the mixture cool completely.
   • Whisk in the egg white until fully combined and the mixture turns glossy.
   • Measure out and reserve 1 tablespoon of the filling.
5. Grease an 8½ by 4½-inch loaf pan.
   • Press down on the dough to deflate it, then transfer it to a lightly floured counter.
   • Press and roll the dough into an 18 by 14-inch rectangle, with the long side parallel to the counter edge.
   • Spread the remaining filling over the dough, leaving a ½-inch border around the edges.
6. Roll the dough away from you into a firm cylinder, keeping the roll taut by tucking it under itself as you go.
   • Pinch the seam closed, then reshape the cylinder as needed to be 18 inches in length with a uniform thickness.
   • Position the cylinder seam side up and spread the reserved filling over the top.
   • Fold the cylinder on top of itself and pinch the ends to seal.
7. Gently twist the double cylinder twice to form a double figure eight.
   • Place the loaf seam side down in the prepared pan, pressing the dough gently into the corners.
   • Cover loosely with greased plastic and let it rise until the loaf is level with the lip of the pan, for 1½ to 2 hours.
8. Adjust the oven rack to the lower-middle position and preheat the oven to 350 degrees Fahrenheit.
   • Gently brush the loaf with the egg mixture and bake until deep golden brown and the loaf registers 190 to 195 degrees Fahrenheit, for 40 to 45 minutes, rotating the pan halfway through baking.
   • Let the loaf cool in the pan for 15 minutes.
   • Remove the loaf from the pan and let it cool completely on a wire rack, for about 3 hours, before serving.