In a large bowl, combine 330 grams of room temperature water with 20 grams of fresh lemon juice. Stir in 50 grams of your bubbly sourdough starter until fully combined.

In a separate bowl, rub 1 tablespoon of lemon zest into 50 grams of sugar until fragrant. Add 500 grams of bread flour and 10 grams of salt, whisking until blended.

Incorporate the dry mixture into the wet mixture, stirring gently until no dry flour remains. Cover the bowl with a damp cloth and let the dough rest for 30 minutes.

Perform a series of stretch and folds in the bowl for about 4 times. Let it rest for another 30 minutes before incorporating 200 grams of blueberries.

Cover the bowl and let the dough rise at room temperature for 10-14 hours.

Turn the dough onto a floured surface and shape it into a tight ball. Transfer to a floured banneton, seam side up.

Place the banneton in the refrigerator for cold proofing for 8 hours or up to 2 days.

Preheat your Dutch oven to 450°F about 30 minutes before baking.

Transfer the dough onto parchment paper, score the top, place it in the hot Dutch oven, cover, and bake for 25 minutes. Remove lid and bake for an additional 10-15 minutes.

Transfer the loaf to a wire rack and allow it to cool for at least 2 hours before slicing.