Seeded Sourdough

• In a large bowl add the starter and water and mix to combine. Add the vital wheat gluten, whole wheat flour, all-purpose flour, and salt and mix to combine, just a couple of minutes. Cover loosely and let rest an hour.
• MEANWHILE, in a small bowl add the white sesame seeds, the flax seed, and the fennel seeds and pour the hot water over. Cover and let rest while the dough is resting.
• After the aforementioned rest for an hour, mix the dough over onto itself, turn to stretch and fold. Add about half the seed soak and half the sunflower and (if using) half the nigella seeds. Do stretches an folds until combined, then add the rest of the seeds and continue stretching and folding. NOTE: if it seems dry or too wet, add water or flour a teaspoon at a time. A lot of this hydration will depend on how much water you added to the seeds, seasonal humidity, etc.
• Every 30 minutes for the next two hours do 10-20 stretch and folds then cover and let rest. A bit of olive oil will help reduce sticking when doing the stretch and folds. (See notes.)
• At the end of 2 hours and after your last stretches and folds, cover and let rest at room temperature or in the refrigerator until ~50% larger.
• Prepare your two bannetons with all-purpose and/or rice flour.
• Remove dough to a floured surface and gently punch down. Divide in two (should be about 660 grams each loaf) and fold and shape into a round. Sprinkle the top with the black sesame seeds and gently press them into the loaf. Turn upside down into banneton (I sprinkled a few seeds into the banneton, too). Repeat with the other loaf, cover, and let both rest for 30 minutes.
• Pop into the refrigerator and let ferment overnight or up to two nights. This bulk ferment phase really helps with the development of the sour flavor.

Baking

• Put a pan of hot water on the lowest rack or bottom of the oven.
• Put your two small Dutch ovens in the oven.
• Preheat oven to 425°F Convection (220°C Fan) or 450°F regular (230°C non-fan)
• Let sit for 10+ minutes after coming to temp to make sure your Dutch ovens are thoroughly preheated.
• Turn each dough out onto parchment paper (I use half sheets of parchment paper for each boule), dust with all-purpose or rice flour, give a couple of slashes, and put into the heated Dutch ovens.
• Bake, covered, for 18 minutes.
• Remove the lids from the Dutch ovens, rotate, reduce the heat 25°F and cook another 22 minutes.
• Remove the Dutch ovens from the oven, remove the loaves from the Dutch ovens, and return the loves to the rack in the oven.
• Turn the oven off and prop the door open.
• Let loaves rest at least 90 minutes before eating.