# 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 fresh lemon juice
12 - 1 tablespoon cornstarch
→ Optional Glaze
13 - 1/2 cup powdered sugar
14 - 1 to 2 tablespoons fresh lemon juice
# Step-by-Step Guide:
01 - In a small saucepan, combine blueberries, sugar, and lemon juice. Cook over medium heat while stirring until berries burst and release juice, approximately 5 to 7 minutes. Stir in cornstarch and continue cooking for 1 to 2 minutes until thickened. 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 combined. Gradually add flour and knead for 8 to 10 minutes until dough becomes smooth and elastic.
03 - Place dough in a lightly greased bowl and cover. Let rise at room temperature until doubled in size, approximately 4 to 6 hours depending on starter activity.
04 - Turn dough onto a floured surface and roll into a 9 by 16 inch rectangle. Spread cooled blueberry swirl evenly over dough, leaving a 1 inch border around edges.
05 - Roll dough tightly from the short end to form a log. Place seam-side down in a greased 9 by 5 inch loaf pan.
06 - Cover loaf and let rise at room temperature for 1 to 2 hours until puffy and nearly doubled in size.
07 - Preheat oven to 350 degrees Fahrenheit. Bake for 35 to 40 minutes until golden brown and loaf sounds hollow when tapped on bottom.
08 - Optional: Mix powdered sugar and lemon juice to create a glaze consistency. Drizzle over cooled bread using a pastry brush or spoon.