Summary

Instructions

1. 1

   Make the dough: In the bowl of a stand mixer, whisk warm milk (about 110°F/43°C), yeast, and 1 tablespoon of the sugar. Cover and let sit 5 minutes until foamy.

2. 2

   Add remaining sugar, softened butter, lemon zest, egg, vanilla, salt, and most of the flour. Mix, then knead (stand mixer or by hand), adding remaining flour as needed, until a soft, slightly tacky dough forms.

3. 3

   First rise: Place dough in a lightly greased bowl, cover, and let rise in a warm spot until roughly doubled, 2–4 hours (this rich dough can take longer). Tip: For a warmer environment, preheat oven to 150°F (66°C), turn it off, place covered dough inside, and leave the door slightly ajar.

4. 4

   Make the blueberry filling (while dough rises): In a saucepan, combine fresh blueberries, granulated sugar, and lemon juice. Cook over medium heat, stirring, until boiling and reduced to a jammy consistency (about 215–220°F/102–104°C). You should have about 1/2 cup. Transfer to a shallow, heat-safe dish and cool completely; it will thicken as it cools.

5. 5

   Make the crumble (can be made ahead and chilled): In a bowl, combine flour and brown sugar. Cut in the cold cubed butter until pea-sized crumbs form. Refrigerate until needed.

6. 6

   Shape: Punch down risen dough. On a lightly floured surface, roll into a 9×15-inch rectangle. Spread the cooled blueberry filling evenly over the surface.

7. 7

   Starting from one edge, roll up the dough into a tight log (as for cinnamon rolls). Fold the log in half and twist into a figure-8, keeping the filling enclosed.

8. 8

   Transfer to a greased loaf pan, tucking ends under if needed. Cover and let rise until puffy, about 1–1.5 hours.

9. 9

   Finishing before baking: Brush the top with beaten egg white. Use a skewer or toothpick to poke several small holes on the surface to vent steam and help prevent layers from separating.

10. 10

    Top with crumble: Sprinkle the chilled brown sugar crumble evenly over the loaf.

11. 11

    Bake until deep golden and cooked through, about 50 minutes. If the top browns too quickly, tent loosely with foil after about 30 minutes and continue baking until done.

12. 12

    Lemon icing: Whisk confectioners’ sugar, lemon juice, and milk/cream to a pourable consistency. Drizzle over the warm babka (optional).

13. 13

    Cool slightly, then slice and serve. Every loaf’s swirl pattern will be unique!