The Starter Jar's Ultimate Sourdough Babka: A Data-Driven Guide

Step 1

In a large bowl, combine the active sourdough starter, lukewarm milk, egg, egg yolk, and granulated sugar. Mix well until combined.

Step 2

Add the bread flour and salt to the wet mixture. Mix with a spatula or your hands until a shaggy dough forms and no dry flour remains.

Step 3

Turn the dough out onto a lightly floured surface and knead for 5-7 minutes until it starts to become smooth. Cover and let rest for 30 minutes.

Step 4

Gradually add the softened butter, one cube at a time, kneading each piece fully into the dough before adding the next. This will take 10-15 minutes until the dough is smooth, elastic, and passes the windowpane test.

Step 5

Place the dough in a lightly oiled bowl, cover, and let it bulk ferment at room temperature (around 70-75°F / 21-24°C) for 3-4 hours, performing a set of stretch and folds every hour.

Step 6

After the initial bulk, transfer the covered bowl to the refrigerator for 8-16 hours (or up to 48 hours). This cold ferment develops flavor and makes the dough easier to handle.

Step 7

While the dough chills, prepare the chocolate filling. In a medium bowl, cream together the softened butter and powdered sugar until light and fluffy.

Step 8

Stir in the cocoa powder, finely chopped dark chocolate, vanilla extract, and pinch of salt until well combined. Set aside at room temperature.

Step 9

Remove the dough from the refrigerator and let it warm up slightly for 30 minutes. On a lightly floured surface, roll the dough into a large rectangle, approximately 12x18 inches (30x45 cm) and about 1/4 inch thick.

Step 10

Evenly spread the chocolate filling over the entire surface of the rolled-out dough, leaving a small border (about 1/2 inch) along one long edge.

Step 11

Starting from the long edge opposite the border, carefully roll the dough into a tight log. Pinch the seam closed to secure the roll.

Step 12

Transfer the log to a baking sheet lined with parchment paper and chill in the freezer for 15-20 minutes, or refrigerator for 30-45 minutes. This firms up the log for easier cutting.

Step 13

Using a sharp knife, slice the chilled log lengthwise down the center, creating two equal halves. Turn the cut sides up.

Step 14

Cross one half over the other, keeping the cut sides facing up, forming an 'X'. Gently twist the two halves around each other to create a braided appearance.

Step 15

Carefully transfer the braided dough into a greased 9x5 inch (23x13 cm) loaf pan.

Step 16

Cover the loaf pan loosely with plastic wrap or a damp towel and let it proof at room temperature for 2-4 hours, or until visibly puffy and almost doubled in size. The dough should feel soft and airy.

Step 17

Towards the end of the proofing time, preheat your oven to 375°F (190°C).

Step 18

Bake for 30 minutes, then loosely tent with foil to prevent over-browning and continue baking for another 15-20 minutes, or until the internal temperature reaches 200-205°F (93-96°C).

Step 19

While the babka bakes, prepare the simple syrup by combining sugar and water in a small saucepan. Bring to a simmer, stirring until the sugar dissolves. Remove from heat.

Step 20

As soon as the babka comes out of the oven, brush the entire top generously with the simple syrup. This adds shine and moisture.

Step 21

Let the babka cool in the pan for 15-20 minutes before carefully removing it to a wire rack to cool completely. Slice and enjoy The Starter Jar's ultimate sourdough babka!