A rich, swirled chocolate bread made with a tangzhong-enriched dough and a decadent chocolate filling. Finished with simple syrup for a glossy, moist crumb.
In a stand mixer with a dough hook, combine flour, sugar, yeast, and salt. Add the milk, egg + yolk, and all the cooled tangzhong. Mix on low for 2–3 minutes until a shaggy dough forms.
Increase to medium speed and mix for 5–6 minutes until the dough is firm, elastic, and tacky.
Add the butter 1–2 tablespoons at a time, mixing until each addition is fully incorporated before adding the next. Scrape bowl/hook as needed. Once all butter is added, mix 7–10 minutes on medium speed until the dough is smooth, glossy, and can stretch thin without tearing (passes the windowpane test).
Shape the dough into a ball and place in a lightly greased medium bowl. Cover with plastic wrap. Then, choose one of the following rise options:
Same-Day (Faster): Let dough rise at room temperature for 1½ to 2 hours, until slightly puffy. Then transfer to a plastic wrap-lined sheet tray, gently press into a rectangle, cover, and refrigerate for at least 1 hour.
Overnight (Preferred): Let dough rest (covered) at room temperature for 1 hour to kickstart fermentation. Then transfer to a plastic-lined sheet tray, gently press into a rectangle, cover, and refrigerate overnight (8–24 hours).
Tip: Shaping into a clean rectangle here makes rolling later much easier.
Line and grease an 8.5 x 4.5 inch (22 x 11 cm) loaf pan with parchment paper, leaving a bit of overhang on the long sides for easy removal after baking.
On a lightly floured surface, roll the chilled dough to an 11 x 22 inch (28 x 56 cm) rectangle (short side facing you).
Spread chocolate filling evenly all the way to the edges. Then, roll up tightly from the short (11 inch) side into a log.
Place log on a tray, cover, and chill for 20–30 minutes to firm up for clean slicing.
Trim off ends with a sharp knife, then slice log lengthwise into two equal strands.
With cut sides facing up, twist strands tightly together 3–4 times.
Gently press and compact the twisted log to fit your loaf pan snugly.
Transfer to the prepared pan. Cover and let rise in a warm spot for 1.5–2 hours, until puffy.
Tip: Take a before/after photo to help gauge rise.
Bake for 50–55 minutes, placing the pan on a baking sheet. Tent with foil after 25–30 minutes to prevent over-browning. Internal temp should read 190–195°F (88–90°C).
While baking, make the simple syrup by cooking the sugar and water in a small saucepan until sugar has dissolved.
When the babka comes out of the oven, pour the syrup over it immediately while still hot — use all of it.
Let the loaf cool completely in the pan before removing. Serve slightly warm. Wrap tightly once cooled and keep 2–3 days at room temp, or freeze for longer storage.