The Starter Jar's Best Sourdough Chocolate Babka: A Masterpiece Made Easy

Step 1

In a large mixing bowl, combine the active sourdough starter, flour, granulated sugar, salt, egg, and warm milk. Mix with a spoon or your hands until a shaggy dough forms.

Step 2

Turn the dough out onto a lightly floured surface and knead for 5-7 minutes until it starts to become smooth.

Step 3

Gradually add the softened butter cubes, one at a time, kneading each piece in completely before adding the next. Continue kneading for another 8-10 minutes until the dough is smooth, elastic, and passes the windowpane test.

Step 4

Place the dough in a lightly oiled bowl, cover it, and let it rise at room temperature (70-75°F / 21-24°C) for 3-4 hours, or until visibly puffy. Then, transfer to the refrigerator for 8-12 hours for a slow, cold fermentation.

Step 5

While the dough chills, melt the chopped dark chocolate and butter together in a heatproof bowl over a double boiler or in the microwave in 30-second intervals, stirring until smooth. Stir in the powdered sugar, cocoa powder, and milk until well combined and smooth. Let it cool slightly, but remain spreadable.

Step 6

Remove the chilled dough from the refrigerator. On a lightly floured surface, roll the dough into a large rectangle, approximately 12x18 inches (30x45 cm).

Step 7

Evenly spread the cooled chocolate filling over the entire surface of the dough, leaving a small border along one long edge.

Step 8

Tightly roll the dough from one long edge into a log. Transfer the log to a baking sheet lined with parchment paper and chill in the freezer for 15-20 minutes, or in the refrigerator for 30-45 minutes, to make it easier to cut.

Step 9

Using a sharp knife or bench scraper, cut the chilled log in half lengthwise, exposing the layers of chocolate. Pinch the top ends together, then carefully twist the two halves around each other, keeping the cut sides facing up.

Step 10

Carefully transfer the twisted dough into a lightly greased 9x5 inch (23x13 cm) loaf pan. Cover loosely with plastic wrap and let it proof at room temperature for 1.5-2 hours, or until visibly puffy and almost doubled in size.

Step 11

Preheat your oven to 375°F (190°C). Bake the babka for 35-45 minutes, or until deeply golden brown and cooked through. If the top browns too quickly, loosely tent it with foil. A digital thermometer inserted into the center should read around 200-205°F (93-96°C).

Step 12

While the babka bakes, combine sugar and water in a small saucepan. Bring to a simmer, stirring until the sugar dissolves. Remove from heat and let cool slightly.

Step 13

As soon as the babka comes out of the oven, brush generously with the warm simple syrup. Let it cool in the pan for 15-20 minutes before carefully transferring it to a wire rack to cool completely.