# What You'll Need:
→ Dough
01 - 3 cups bread flour
02 - 1/2 cup active sourdough starter at 100% hydration
03 - 1 cup whole milk, lukewarm
04 - 1/4 cup unsalted butter, softened
05 - 1/4 cup granulated sugar
06 - 1 large egg
07 - 1 teaspoon fine sea salt
08 - Zest of 1 lemon
→ Blueberry Lemon Swirl
09 - 1 cup fresh or frozen blueberries
10 - 1/4 cup granulated sugar
11 - 2 tablespoons lemon juice
12 - 1 tablespoon cornstarch
→ Optional Glaze
13 - 1/2 cup powdered sugar
14 - 1 to 2 tablespoons lemon juice
# How-To Steps:
01 - In a small saucepan, combine blueberries, sugar, and lemon juice. Cook over medium heat, stirring frequently, until the berries burst and release their juice, approximately 5 to 7 minutes. Stir in cornstarch and continue cooking for 1 to 2 minutes until the mixture thickens. Transfer to a bowl and cool completely.
02 - In a large bowl or stand mixer, combine lukewarm milk, sourdough starter, softened butter, sugar, egg, salt, and lemon zest. Mix until incorporated. Gradually add flour while mixing and knead for 8 to 10 minutes until the dough becomes smooth and elastic.
03 - Transfer the dough to a lightly greased bowl and cover with a damp cloth. Let rise at room temperature until the dough doubles in volume, approximately 4 to 6 hours depending on starter activity and ambient temperature.
04 - Turn the proofed dough onto a floured work surface. Roll into a 9 by 16 inch rectangle. Spread the cooled blueberry swirl evenly across the dough surface, leaving a 1 inch border on all sides.
05 - Roll the rectangle tightly from the short end to form a compact log. Place seam-side down into a greased 9 by 5 inch loaf pan, ensuring even distribution.
06 - Cover the pan with a damp cloth and let rise at room temperature for 1 to 2 hours until the dough becomes puffy and nearly doubles in height.
07 - Preheat the oven to 350°F. Bake for 35 to 40 minutes until the crust turns golden brown and the loaf sounds hollow when tapped on the bottom.
08 - If desired, whisk powdered sugar with lemon juice to achieve a drizzling consistency. Once the baked loaf has cooled slightly, drizzle the glaze decoratively across the top surface.
