Prepare the dough:

1. In the bowl of a stand mixer, combine the active sourdough starter, all-purpose flour, white whole wheat flour, and water. Mix on low speed until the flour is hydrated. Note: The dough may be a little on the dry side at this point, but don’t add extra water just yet. The jarred pimentos will contribute extra moisture.
2. Cover the bowl and allow the dough to rest (autolyse) at room temperature for 45 minutes.
3. After the autolyse, add the salt and spices. Mix on low speed until thoroughly incorporated. Cover, and let the dough rest for 15 minutes.
4. Add the drained pimentos, and grated onion. Mix on low speed until evenly distributed throughout the dough. Gradually add the grated sharp cheddar cheese, one half a cup at a time. Mixing after each addition.

Bulk Fermentation:

1. Transfer the dough to a large bowl, Cover and let the dough rest at room temperature for about 2 to 3 hours. During this time, perform a series of stretch and folds every 30 minutes for the first 1 1/2 hours. To do a stretch and fold, wet your hands, then grab one side of the dough, stretch it gently, and fold it over the center of the dough. Repeat this process for all four sides of the dough.
2. After the series of stretch and folds, allow the dough to rest for an additional 1-2 hours at warm room temperature.

Shape the Loaf:

1. Lightly flour your work surface and carefully shape the dough into a round boule. To do this, fold the edges of the dough towards the center, creating tension on the surface. Once the dough is shaped, place it seam side up in a floured lined or unlined 9-inch round proofing basket. The weight of the loaf should be around 1400 grams.

Final Proofing:

1. Cover the dough with a clean kitchen towel or a plastic produce bag to prevent drying. Allow the dough to proof at room temperature for about hour, then cover tightly and place in the refrigerator overnight.
2. Note: Due to the moisture from the pimentos and cheese, I found this bread performs better when given a cold ferment in the refrigerator overnight. The cold ferment makes the loaf easier to score and keeps it from flattening as much when removing from the basket.

Baking:

1. The next day, about 30 minutes before you are ready to bake, preheat your oven to 475°F (246°C). Place a Dutch oven or bread cloche (aka bread pot) on the lower shelf and allow to preheat with the oven.
2. Remove the proofed loaf from the refrigerator and carefully invert it seam side down onto a piece of parchment paper. Score the top of the dough with a sharp knife or bread lame to allow for controlled expansion during baking.
3. Take the preheated bread pot out of the oven and place the lid and bottom on heavy towels to protect your counter. Transfer the shaped and scored loaf (on the parchment) to the bottom of the preheated pot.
4. Place the bread pot, with its lid, in the oven and bake for 20-25 minutes with the lid on. Then, remove the lid and continue baking for an additional 20-25 minutes, or until the crust is golden brown.
5. Remove the loaf from the oven and let it cool on a wire rack for at least 1 hour before slicing. This allows the crumb to set and results in a better texture.