Lemon Blueberry Sourdough Loaf (Printable Version)

Tangy sourdough loaf with blueberry swirl and lemon zest topped with a golden crumble.

# What You'll Need:

→ Dough

01 - 2 3/4 cups bread flour
02 - 1/3 cup active sourdough starter
03 - 1/4 cup granulated sugar
04 - 1 large egg
05 - 1/2 cup whole milk, lukewarm
06 - 1/4 cup unsalted butter, softened
07 - 1 teaspoon fine sea salt
08 - Zest of 1 large lemon

→ Blueberry Swirl

09 - 1 1/2 cups fresh or frozen blueberries
10 - 1/4 cup granulated sugar
11 - 1 tablespoon lemon juice
12 - 1 tablespoon cornstarch

→ Crumble Topping

13 - 1/3 cup all-purpose flour
14 - 2 tablespoons unsalted butter, cold and cubed
15 - 2 tablespoons light brown sugar
16 - Pinch of salt

# Cooking Steps:

01 - In a stand mixer bowl, combine bread flour, sugar, salt, and lemon zest. Add sourdough starter, egg, and lukewarm milk, mixing to form a shaggy dough.
02 - With mixer on low speed, add softened butter in pieces, mixing until fully incorporated and dough is smooth and elastic, approximately 8 to 10 minutes.
03 - Place dough in a lightly greased bowl, cover, and let rise in a warm place until doubled in volume, about 2 hours.
04 - In a small saucepan, combine blueberries, sugar, and lemon juice. Cook over medium heat until berries burst, approximately 5 minutes. Stir in cornstarch and simmer until thickened, 2 to 3 minutes. Cool completely.
05 - Mix flour, brown sugar, and salt in a bowl. Cut in cold butter until mixture resembles coarse crumbs. Chill until needed.
06 - Once dough has risen, punch down and roll out on a floured surface to a 10 by 14-inch rectangle. Spread cooled blueberry mixture over dough, leaving a 1-inch border. Roll up tightly from the short side to form a log.
07 - Place rolled dough seam-side down in a greased 9 by 5-inch loaf pan. Cover and let rise until puffy, about 1 hour.
08 - Preheat oven to 350°F. Brush loaf with milk or beaten egg if desired, and sprinkle evenly with crumble topping. Bake for 50 to 55 minutes, tenting with foil after 30 minutes if browning too quickly.
09 - Cool in pan for 15 minutes, then transfer to a wire rack to cool completely before slicing.

# Expert Advice:

01 -
  • That tangy sourdough bite paired with sweet-tart blueberries creates a flavor combination that feels intentional, never cloyingly sweet.
  • The crumble topping gives you that satisfying textural contrast and a buttery crunch with every bite.
  • It's forgiving enough for home bakers but impressive enough to gift to someone you care about.
02 -
  • Cooling the blueberry filling completely is non-negotiable; warm filling will make your dough soggy and mess with the crumb structure.
  • Cold butter in the crumble topping is the secret to that shattered, textured bite; melted butter creates a dense, cakey topping instead.
  • If your frozen blueberries release too much liquid, drain some of it off before adding cornstarch, or you'll end up with a purple soup instead of a filling.
03 -
  • Keep your sourdough starter at room temperature and feed it regularly; an active, bubbly starter is the difference between bread that rises beautifully and bread that sits there looking confused.
  • Don't skip the egg wash or milk brush before adding the crumble topping; that shine signals a professionally baked loaf even though you made it at home.
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