About 4–6 hours before mixing the dough, feed your sourdough starter at a 1:1:1 ratio of starter, flour, and water. Allow it to become active, bubbly, and reach its peak.

In a large mixing bowl, combine 100 g active sourdough starter, 500 g bread flour, 400 g warm water, 50 g granulated sugar, 10 g salt, 3 tablespoons lemon juice, and 3 teaspoons lemon zest.

Mix thoroughly with a Danish dough whisk or sturdy spoon until no dry flour remains.

Cover the bowl and allow the dough to rest at room temperature for 30 minutes.

Perform the first set of stretch-and-folds. Grab one edge of the dough, gently stretch it upward, and fold it toward the center. Rotate the bowl and repeat, completing approximately 12–15 folds.

Cover and rest for another 30 minutes. Repeat this process until you have completed three sets of stretch-and-folds in total. The dough will remain loose and sticky because of its high hydration.

After the final set, cover the bowl and leave the dough in a warm place for approximately 3–6 hours for bulk fermentation. Look for noticeable expansion, bubbles, and a lighter, aerated texture rather than relying only on the clock.

Cover the fermented dough and refrigerate overnight.

The following morning, line a baking pan with parchment paper. Drizzle the 30 g olive oil evenly over the parchment.

Carefully turn the chilled dough into the prepared pan. Lightly oil your fingertips and gently stretch the dough toward the edges without forcing out the accumulated air.

Cover and leave in a warm place for approximately 4–5 hours. The dough should become visibly puffy with plenty of bubbles beneath the surface.

Preheat the oven to 400°F (204°C).

Scatter the fresh blueberries evenly over the dough.

Pour the melted butter across the surface.

Using your fingertips, gently press deep dimples across the dough, pushing some blueberries slightly into the surface.

Bake the Sourdough Blueberry Lemon Focaccia Bread for 30–40 minutes, until lightly golden and the center reaches approximately 200°F (93°C).

While the focaccia bakes, whisk the powdered sugar with 2 tablespoons lemon juice. Add additional lemon juice gradually until the glaze is smooth and easily pourable.

Remove the baked focaccia from the pan and transfer it to a wire rack. Discard the parchment paper.

Allow the bread to cool completely to room temperature.

Drizzle generously with the lemon glaze. Let the glaze settle briefly before slicing and serving