Step 1

In a large bowl, combine the flours and 310 grams water. (Water should be room temperature.) Mix just until the water is absorbed by the flour. Cover with plastic wrap and allow to rest for 20 minutes up to 6 hours. (I recommend 90 minutes.)

Step 2

Add the starter and mix in using a Danish dough whisk or your wet hands. Sprinkle the salt over the top and drizzle the remaining 10 grams water over the top. Dimple the salt and water in with your hands, using a clawing motion, until fully combined. Knead the dough in the bowl, folding the dough and using your fist to punch it into the rest of the dough, constantly rotating the bowl, until the dough is not very sticky and uniform. It will be sticky, so keep your hands lightly wet while kneading.

Step 3

Bulk ferment for 3-3½ hours, during which time do three sets of four folds after the 60, 90 and 120 minute marks. For the first fold, sprinkle ¼ of the lemon zest and blueberries just before each fold. (If the dough feels week, do another set of folds and rest for 30 more minutes.)

Step 4

On a lightly floured surface, pre-shape the dough and allow it to rest, uncovered, for 30 minutes.

Step 5

Shape into desired shape and place shaped dough into banneton lightly dusted with rice flour. Make sure to create tension on the outside of the dough before placing it into the banneton. Allow the dough to rest uncovered for 20 minutes.

Step 6

Wrap the banneton in plastic wrap and refrigerate it overnight for 12-18 hours.

Step 7

In the morning, place a Dutch oven in the oven and preheat it 500° F.

Step 8

Just before you plan to bake the bread, take the banneton out of the refrigerator and remove the plastic wrap. Place a piece of parchment paper over the banneton, and place a cutting board on top of the parchment paper. Flip it over and lift up the banneton. (If the bread is sticking to the banneton, gently try to release it.)

Step 9

Score the bread as desired. Remove the Dutch oven from the oven, uncover it, and carefully slide the parchment into the hot Dutch oven. Spray water all over the bread or add 3 ice cubes and immediately cover the Dutch oven. Bake 25 minutes. Remove Dutch oven lid and reduce temperature to 450° F. Bake an additional 10-15 minutes. Allow the bread to cool to room temperature before slicing.