Lemon Blueberry Sourdough Loaf (Printable Version)

Tangy sourdough loaf with blueberries and lemon zest, finished with a buttery crumble topping.

# The Ingredients 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 fresh 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

# Step-by-Step Instructions:

01 - In a stand mixer bowl, combine bread flour, granulated sugar, fine sea salt, and lemon zest until evenly distributed.
02 - Add sourdough starter, egg, and lukewarm milk to the flour mixture and mix on low speed to form a shaggy dough.
03 - Gradually add softened butter in pieces while the mixer runs on low speed, continuing to mix until the dough becomes smooth and elastic, approximately 8 to 10 minutes.
04 - Transfer dough to a lightly greased bowl, cover with a damp towel, and allow to rise in a warm location until volume doubles, approximately 2 hours.
05 - In a small saucepan, combine blueberries, granulated sugar, and lemon juice. Cook over medium heat until berries burst and release their juices, approximately 5 minutes. Stir in cornstarch and simmer until the mixture thickens, 2 to 3 minutes. Transfer to a bowl and cool completely before using.
06 - In a mixing bowl, combine all-purpose flour, light brown sugar, and salt. Cut cold cubed butter into the dry ingredients using a fork or pastry cutter until the mixture resembles coarse breadcrumbs. Refrigerate until ready to use.
07 - Once the dough has doubled in volume, gently punch it down and turn onto a floured surface. Roll out to a 10 by 14-inch rectangle of uniform thickness.
08 - Spread the cooled blueberry mixture evenly over the rolled dough, leaving a 1-inch border on all edges to prevent spillage during baking.
09 - Starting from the short side, tightly roll the dough into a log shape. Place seam-side down into a greased 9 by 5-inch loaf pan.
10 - Cover the loaf pan with a towel and allow the dough to rise until puffy and nearly doubled, approximately 1 hour.
11 - Preheat oven to 350 degrees Fahrenheit. Optional: brush the loaf with milk or beaten egg for a glossy finish. Distribute crumble topping evenly across the surface.
12 - Bake for 50 to 55 minutes until golden brown. If the top browns too quickly after 30 minutes, tent loosely with aluminum foil to prevent excessive darkening.
13 - Allow the loaf to cool in the pan for 15 minutes, then turn out onto a wire rack to cool completely before slicing.

# Additional Tips::

01 -
  • The sourdough tang plays beautifully against juicy blueberries and lemon, creating layers of flavor that feel sophisticated without requiring expertise.
  • It's tender and moist enough for breakfast but elegant enough to serve at brunch, which means one loaf covers multiple occasions.
02 -
  • Spreading warm blueberry filling on your dough will literally cook the surface and create a gluey mess, so let it cool completely on a plate first—this changed everything for me after my second attempt taught me the hard way.
  • Keeping your crumble butter cold until it hits the oven is what gives you those golden, craggy bits instead of a dense, cakey topping that tastes like regular streusel.
03 -
  • If your kitchen is cold, create a warm proof box by turning your oven on to the lowest setting for 2 minutes, then turning it off and placing your covered bowl inside—this stable warmth prevents over-proofing.
  • The egg wash before baking is optional but worth doing because it gives you that professional-looking golden sheen that makes people think this came from a bakery.
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