Step 1
In the bowl of a stand mixer with the hook attachment, combine bread flour, sourdough starter, water, sugar, and oil.
Step 2
On low speed, mix until dough pulls away and cleans the sides of the bowl; about 3 to 5 minutes. Cover mixer bowl loosely with plastic wrap to prevent dough from drying out, and allow to rest 15 minutes.
Step 3
Sprinkle fine sea salt over the dough. Mix until salt is incorporated into the dough and forms a smooth ball; about 5 minutes.
Step 4
Grease a large bowl with a small amount of oil. Place dough into the bowl, flipping the ball of dough to lightly grease the top of the dough. Flip ball over. Cover bowl with plastic wrap and let it rest in a warm place, free from drafts. Let dough double in size. This will take from 1 to 2 hours. Once doubled in size, sprinkle the bottom of a dutch oven with cornmeal; this will prevent the sourdough from sticking to the bottom of the pot.
Step 5
Being careful not to deflate the dough too much, transfer the dough to a very lightly floured surface. Shape and round the dough by moving the dough in a circular motion by pushing and pulling the dough, making sure the bottom side stays in contact with the work surface.
Step 6
Once rounded and satisfied with the shape, place the sourdough into the prepared dutch oven. Cover with the lid. Let it rise again until almost doubled; about an hour. Meanwhile, preheat oven to 450℉ (220℃).
Step 7
Once dough has proofed and is ready to go in the oven, dust the top of the dough lightly with bread flour. Take a sharp paring knife or a serrated knife and carefully slash a quarter inch deep “#” or “X” or “/” into the top of the dough.

Step 8
Place Dutch oven with the lid on, into the hot oven. Bake for 10 minutes. Reduce oven temperature to 400℉ (200℃) and bake for 10 minutes. Take lid off. Bake for an additional 15 to 25 minutes or until the internal temperature reaches 212℉ (100℃). The crust should be a deep golden brown and when tapped should produce a hollow sound. It should also feel light for its size.

Step 9
Take out of oven, and immediately remove sourdough from the Dutch oven. Cool completely on a wire rack before cutting. Bread can be kept up to 3 days well wrapped in plastic wrap at room temperature or frozen for up to 2 weeks or longer.