Add all ingredients to the bowl of a stand mixer fitted with a dough hook. Mix on low until everything is incorporated, scraping down the sides if needed. Increase to medium-high speed and knead for 10 minutes, until the dough is soft, smooth, and pulling away from the sides of the bowl.
Transfer the dough to a greased bowl. Cover and bulk ferment for 6-10 hours, or until doubled in size. (My kitchen is about 68°F and it takes the full 10 hours — timing will vary depending on your space.)
Turn the dough out onto a clean surface. Lightly dust with rice flour and gently shape into a ball by pushing the dough away from you and pulling it back. Cover and rest for 15–30 minutes.
Flip the dough seam-side up and gently stretch it into a rectangle. Roll from the short side into a tight log, tucking the sides underneath as you go. Pull the dough toward you to create surface tension.
Place the dough into a parchment-lined or greased loaf pan, seam side down. Cover and proof for about 2 hours, or until the dough rises about 1 inch above the rim of the pan.
Preheat the oven to 500°F. Score the top of the loaf, then cover the loaf pan with a second loaf pan to create steam. Place in the oven and immediately reduce the temperature to 375°F.
Bake covered for 25 minutes, then remove the top pan and bake uncovered for an additional 20 minutes, or until the internal temperature reaches 205°F.
Spread butter over the top of the loaf (optional). Cool for 1 hour before slicing.