In a large mixing bowl, combine 375g warm water with 100g of active starter until mostly combined. I like to use a Danish dough whisk, but anything will work.

Add 500g bread flour and 14g salt to the bowl and mix until a shaggy dough forms. Knead the dough with your hands until all the shaggy bits are incorporated.

Cover the bowl and set aside for 45 - 60 minutes.

Uncover the bowl and using damp hands, grab the dough and gently pull it until the flap is long enough to fold over itself, then fold the flap, rotate the bowl 90 degrees, and repeat around 8 times. This is a higher hydration sourdough so it needs the extra manipulation. This is considered one set of stretch and folds. Recover the bowl, and set it aside for 30 minutes.

Meanwhile, zest a large lemon and toss the zest with 30g (2 tablespoons) granulated sugar and set aside until the next stretch and fold.

Turn the dough onto a lightly floured work surface, I like to use my large wooden cutting board. If the dough is pulling apart from the lemon zest inclusions, give the counter and the dough a generous dusting of flour and knead the dough for a few minutes until it comes together.

Press the dough outwards with your fingers and then carefully stretch the dough out into a large rectangle. I find it helps to gently grasp a side of the dough and flap while I pull on it a little bit, then move over a bit before repeating. If the dough begins to tear or resists stretching, allow it a short 5-10 minute rest before continuing.

Distribute 175g blueberries and sprinkle the 25g (2 tablespoons, packed) brown sugar evenly across the surface pf the dough, reserving about 1/4 each.

Fold up the bottom of the rectangle about 1/3 of the way up, like you'd fold a letter. Sprinkle the remaining add ins on the pieces you fold up. Fold the top of the dough over the bottom. Roll the dough up in log. Return to the bowl and cover.

Set aside for 2 hours to bulk ferment. I like to use a reusable shower cap for covering my bowls, the patterns are fun, funky, and bright, but they also work amazingly well, are lined with plastic to help keep the moisture in the dough, and are reusable for ages. It is important to keep the dough bowl somewhere warm to encourage the microbes to work quickly!

Uncover the dough and transfer to a work surface or countertop. Gently press and spread the dough into a large rectangle. We want to work gently with the blueberries, to avoid bursting them open.

Fold up the bottom third of the dough as though you were folding a letter, and then fold the top down.Rotate the dough 90 degrees and roll up into a large log.

Pick up the dough with a dough scraper and flip it over, gently press the dough flat then roll it again. Pinch the ends if you're making a batard or tuck them in if your making a boule.

Prove the blueberry lemon sourdough loaf in the banneton for 2 hours in a warm place before covering and placing in fridge to cold retard for up to 3 days. If you want to bake it right after proving, you're welcome to, but the flavor is better after resting in the fridge.

Once the oven is preheated, invert the banneton onto a sheet of parchment paper.

Use a lame, sharp knife, or clean razor blade to score the dough, I usually like to make one deep curved slash, but you can get as fancy as you like!

Bake the dough at 450f covered for 30 minutes and uncovered at 450f for 10-15 minutes, or until the loaf is cooked through and the crust is nicely browned. You can test the doneness of the loaf with an instant-read thermometer. Bread is cooked once it reaches 205 - 210 degrees Fahrenheit internal temperature.

Remove baked bread from the dutch oven and transfer it to a wire mesh cooling rack to cool completely before slicing. I like to leave it for at least 2 hours before slicing, as slicing too soon can affect the crumb and texture of your loaf.