Combine flour, yeast and salt in a large bowl. Stir with a fork, whisk or spoon to thoroughly mix them together.
In a measuring cup, combine buttermilk, olive oil and enough room temperature water to measure 1-1/2 cups total (you can also use just 1-1/2 cups water).
Slowly pour liquid into the dry ingredients, stirring with a large wooden spoon or spatula to create your dough. Carefully stir, especially checking the bottom, to make sure no dry flour remains.
Cover the bowl with plastic wrap and set aside in a draft-free place. Let the dough rise, undisturbed, for 5 hours.
Note: At this point, you can proceed to the next step now and be baking it in about an hour. But we recommend putting the plastic-covered bowl in the fridge overnight—or even longer, up to two weeks. This will give the dough time to develop more flavor and a sturdier structure, making it less soft white bread in nature. When you're ready to continue, take it out of the fridge and proceed with the next step.
Butter the inside of your loaf pan and dust it with flour. Set aside.
Turn the dough out on a lightly floured surface (I used a nonstick silpat and was glad I did). A flexible dough scraper or steel bench scraper can be quite helpful in wrangling the dough. The dough is quite sticky at this point, but don’t worry.
Flour your hands and the top of the dough, and gently shape it into a rectangle about 8 inches by 12 inches. Gently is key here—you don’t want to squash the bubbles that have formed inside. Fold 1/3 of the dough to the center, then the remaining 1/3 over on it, making it roughly loaf pan-sized shaped. Using your scraper, free it from the work surface and place it in the loaf pan, folded side down.
Cover the pan with a clean dish towel and set aside, again in a draft-free place, and let it rise for at least 1 hour, preferably longer. If your dough came from the fridge, let it rise about 1-1/2 to up to 5 or 6 hours to come more to room temperature and to rise more. That 5 to 6 hours has now become our standard.
Preheat oven to 425ºF with a rack in middle position.
Using a sifter or fine-mesh sieve, lightly dust the top of the loaf with more flour.
Bake until it is golden brown, about 25 – 30 minutes. Not sure if it’s done? Tap the top of the loaf—if it sounds hollow, it’s done.
Turn bread out onto a cooling rack and let cool completely before slicing and eating.