Combine all the ingredients gently in a large bowl until just incorporated, and allow the mixture to rest for 10 minutes. Adjust the milk slightly if the dough appears too stiff; it should be tacky yet manageable. Perform several sets of stretch-and-fold techniques with moist hands, allowing 5-minute intervals between each. Once the dough becomes smooth and exhibits strong gluten strands, shape it softly into a ball. Cover the bowl and leave it to ferment at room temperature (65℉) for 10 to 12 hours.

Reinvigorate the dough with one stretch and fold, then rest it for 10 minutes. Grease two loaf pans (cast-iron or glass preferred) with butter and set them aside. Lightly flour a work surface and divide the dough into two equal portions. Shape each by flattening into a rectangle, folding the top third downward and the bottom third upward. Allow it to rest briefly, repeat the folding in the opposite direction, and then rest the shaped dough seam-side down for 5 minutes. Transfer to the prepared pans for the final rise until doubled in size.

Heat the oven to 400℉. Just before baking, score each loaf down the center using a razor or lame and mist the tops with filtered water. Place the pans side by side in the center rack and bake for 30 minutes, rotating halfway through. Cool in pans for 5 minutes, then release the loaves onto wire racks to cool fully.