Mix flour and water and let the dough autolyse for an hour.
Add salt and sourdough starter and knead the dough for 5-10 minutes. Let the dough rest for 30 minutes.
Add the rolled oats.
Stretch and fold the dough 4 times, or until it doesn't feel slack anymore. Repeat the stretch and fold process two times with 30 minutes of resting time in between.
Let the dough ferment for an additional 3 hours or until the dough has increased about 50-70% in volume. Try to find a warm place, preferably 80°F/27°C
Dump out the dough on a lightly floured surface and pre-shape it into a round. Let the dough relax for 15 to 30 minutes.
Stretch the dough and fold it from two sides, and roll it into a tubular shape.See video, link in recipe notes. Place the dough into a lightly greased bread form, about 25x11x7 cm / 10x4,5x3 inches in size
Cover the dough or place it in a food proof plastic bag. Let it proof for 1-1,5 hours, or until the dough reaches the upper edge of the bread form. Pre-heat the oven to 480°F/250°C.
Bake it for 35-40 minutes. Lower the heat if needed after 30 minutes to prevent the bread from getting burnt.
Take out the bread from the oven and let it cool for a while. When you can handle the bread form, remove the bread carefully.