Ingredients

Makes 2 Loafs

430 g Room Temperature Peeled Mashed Potato at room-temperature (See Note)
740 g All-purpose white flour
(Optional) A few grams 10-30 g of Whole Wheat
530 g Water at room temperature water
135 - 150 g Starter
22 - 30 g salt
Your choice of flavoring - Thyme, Rosemary etc.

NOTE: When cooking the mashed potatoes, ensure that the potatoes are peeled. As well, do not cook the mashed potatoes with salt, oil, milk or butter.

Recipe

Add the 740 g flour into a large mixing bowl. Next, add the 430 g of mashed potatoes and mix well with the flour, being sure to remove any large of clumps potatoes with your fingers or a fork. Then, add the 530 g of water and mix well. Let sit for at least 30 minutes to autolyse the flour (allow gluten to form).
After 30 minutes, add the starter, salt, and flavoring and mix well in your usual manner. After mixing, the dough will may be significantly hydrated and not have much shape, add additional whole wheat flour (or all-purposed flour) if you desire a less hydrated mix. Let the dough rise for 4-8 hours until about doubled.
During the bulk rise, the dough will need 3-5 folds. Use more folds (4-5) if the dough is significantly hydrated, it will help it have more shape, and develop additional gluten.
Once the dough has doubled, remove the dough from its bulk bowl and place onto a well floured cutting bored. Cut the dough ball in half. Each dough ball might still be significantly wet and shapeless, if so, knead and work the dough until it has more shape. Form the dough into balls and place in proofing basket in the usual way.
Let the dough proof for 30-45 minutes (or overnight in the refrigerator). Meanwhile, preheat an oven with a cast iron in it to 450 degrees F. Once the dough has proofed, cook the bread with lid on for 30 minutes, then remove the lid from the cast iron and cook until golden brown, 5-20 minutes.