1. Combine and Mix the Dough: In a large bowl, combine the active sourdough starter, warm water, and salt. Stir until the starter is mostly dissolved. Add the bread flour and mix with a Danish dough whisk or a sturdy spoon until no dry flour remains and a shaggy dough forms. Cover the bowl with a damp kitchen towel or plastic wrap and let it rest for 30 minutes (this is called autolyse, which helps the flour hydrate).

2. Perform Stretch and Folds: After the rest, uncover the dough. With wet hands, gently grab a portion of the dough from one side, stretch it upwards, and fold it over itself towards the center. Rotate the bowl a quarter turn and repeat this process three more times, completing one set of “stretch and folds.” Cover the bowl and let it rest for 30 minutes. Repeat this set of stretch and folds 3-4 more times, every 30 minutes, for a total of 4-5 sets. The dough will become smoother and more elastic with each set.

3. Bulk Fermentation (First Rise): After the last set of stretch and folds, cover the bowl and let the dough rise at room temperature (around 70-75 F / 21-24 C) for 4-6 hours. The dough should visibly increase in volume by about 50-75% and appear bubbly. You should see small bubbles on the surface.

4. Shape the Dough for the Loaf Pan: Lightly grease a standard 9×5-inch loaf pan with olive oil. Gently turn the dough out onto a lightly floured surface. Gently pat it into a rough rectangle. Fold the top third of the rectangle down to the center, then fold the bottom third up over the top. Gently roll the dough into a log shape, sealing the seam along the bottom. Place the shaped dough seam-side down into the prepared loaf pan.

5. Final Proof (Second Rise): Cover the loaf pan loosely with plastic wrap or a damp towel. Let the dough proof at room temperature for 2-4 hours, or until it has risen to about 1 inch above the rim of the loaf pan. Alternatively, you can cold proof it in the refrigerator overnight (8-12 hours) for a deeper flavor development. If cold proofing, let it sit at room temperature for 30-60 minutes before baking.

6. Preheat Oven and Bake: Preheat your oven to 425 F (220 C) with a rack in the center. Once preheated, place the loaf pan in the oven. Bake for 20 minutes, then reduce the oven temperature to 375 F (190 C) and continue baking for another 20-25 minutes, or until the crust is golden brown and the internal temperature reaches 200-210 F (93-99 C). If the top is browning too quickly, you can loosely tent it with aluminum foil.

7. Cool Completely: Carefully remove the bread from the loaf pan immediately after baking and place it on a wire rack to cool completely. This is a critical step! Do not slice into hot bread, as it will be gummy and compromise the texture. Let it cool for at least 1-2 hours before slicing.