Lemon Blueberry Sourdough Swirl (Printable)

Tangy sourdough loaf with blueberry swirl, lemon zest, and a buttery crumble topping, perfect for breakfast or snack.

# Components:

→ 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

# Method:

01 - In a stand mixer bowl, combine bread flour, granulated sugar, fine sea salt, and lemon zest.
02 - Add the active sourdough starter, egg, and lukewarm milk. Mix until a shaggy dough forms.
03 - With the mixer on low speed, add softened butter in pieces, mixing until fully incorporated and dough becomes smooth and elastic, approximately 8 to 10 minutes.
04 - Place dough in a lightly greased bowl, cover, and let rise in a warm place until doubled in volume, approximately 2 hours.
05 - In a small saucepan, combine fresh or frozen blueberries, granulated 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. Allow to cool completely.
06 - In a mixing bowl, combine all-purpose flour, light brown sugar, and salt. Cut in cold butter cubes until the mixture resembles coarse crumbs. Refrigerate until needed.
07 - Once dough has risen, punch down and roll out on a floured surface to a 10 by 14 inch rectangle.
08 - Spread cooled blueberry mixture over the dough, leaving a 1 inch border on all sides.
09 - Roll up tightly from the short side to form a log. Place seam-side down in a greased 9 by 5 inch loaf pan.
10 - Cover and allow to rise until puffy, approximately 1 hour.
11 - 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.
12 - Cool in pan for 15 minutes, then transfer to a wire rack to cool completely before slicing.

# Expert Advice:

01 -
  • The sourdough tang keeps this from tasting like regular sweet bread—there's complexity hiding underneath all that comfort.
  • You get three textures in every slice: tender crumb, pockets of blueberry jammy-ness, and that golden buttery crunch on top.
  • Your house will smell incredible for hours, and honestly, that alone is worth making it.
02 -
  • Room temperature matters enormously with sourdough—if your kitchen is cold, your rise will take longer, so be patient and go by how the dough looks, not the clock.
  • Never spread warm blueberry filling on the dough or you'll end up with blue-tinted dough and a soggy center; cooling it completely is non-negotiable.
  • The cornstarch in the filling is your secret weapon against a gummy middle—don't skip it thinking the berries will thicken on their own.
03 -
  • Don't waste time being precious about your sourdough starter discard—this recipe is literally designed to celebrate using what you'd normally throw away, and it'll taste better than anything you'll bake from a dry packet.
  • If you're nervous about the swirl, you can dollop blueberry compote in random pockets instead of spreading it evenly; the effect is less defined but the flavor is just as good and there's less risk of leaks.
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