Make the Dough

• Whisk flour, sugar, and yeast in the bowl of a stand mixer.
• Add the lukewarm milk, eggs, vanilla, and citrus zest. Mix on low until a shaggy dough forms, about 2 minutes.
• Add the salt. Add the softened butter a little at a time. Increase to medium speed and knead 8 to 10 minutes until smooth and slightly tacky.
• Transfer dough to a lightly oiled bowl. Cover and refrigerate overnight (8 to 12 hours). It will puff, not double.

Make the Chocolate Filling

• Melt chocolate and butter together over low heat or in the microwave.
• Stir in cocoa powder, powdered sugar, cinnamon, and salt. Mixture should be spreadable. Let cool slightly.

Shape the Babka

• Remove dough from fridge and divide in half for full loaves, or into 4 to 6 pieces for mini loaves.
• Roll each portion into a 10x16 inch rectangle (smaller for minis).
• Spread filling evenly, leaving a 1/2 inch border.
• Roll into a tight log and pinch the seam.
• Slice lengthwise with a serrated knife. Twist the two cut halves together with cut sides facing up.
• Transfer twisted loaf to a greased or parchment-lined pan. Repeat with remaining dough.

Second Rise & Bake

• Cover loosely and rise 1 1/2 to 2 hours, until puffy and about 1 inch above the pan.
• For streusel: rub flour, sugar, salt, and cold butter together until crumbly. Sprinkle over loaves.
• Preheat oven to 350°F (175°C).

Bake:

• Full loaves: 35 to 40 minutes
• Mini loaves: 20 to 25 minutes
• Loaves are done when deep golden and reach 190°F internally (in the bread, not the chocolate). Tent with foil if browning too fast.

Make the Simple Syrup

• Heat sugar and water in a saucepan until dissolved.
• Brush over hot loaves immediately after baking.
• Cool 15 minutes in the pan, then move to a rack to cool fully.

Notes

Sourdough Variation

• Replace instant yeast with 125 g active sourdough starter. Reduce milk to 120 ml. First rise becomes 6 to 8 hours at room temp or 12 to 18 hours refrigerated.
• Make-Ahead
• Shaped loaves can rise overnight in the fridge. Remove 30 to 45 minutes before baking. Baked babka freezes up to 3 months.

Storage

• Room temp 2 to 3 days, wrapped. Toast slices to refresh.

Filling Variations

• For cinnamon filling:
• 100 g softened butter
• 150 g brown sugar
• 2 tbsp cinnamon
• Spread and shape as usual.

Mini Pan Tips

• Disposable mini paper loaf pans (around 3.1x1.5 in) work great for gifting. https://a.co/d/4INg8Nb