Make sure your sourdough starter is bubbly and active (ideally at its peak after feeding).
Mix all ingredients except salt in a mixing bowl to form a shaggy wet dough. Let sit for 30 minutes.
Mix salt into dough. Pour dough onto a well-floured surface. Knead about 5 minutes, incorporating as little flour as possible (dough will be sticky at first, becoming smoother as you knead).
Form dough into a smooth ball. Oil mixing bowl with olive oil (about a teaspoon/5 ml).
Coat the dough in oil, then place seam side face down. Cover bowl with plastic wrap and allow dough to proof at room temperature overnight or 12 hours.
Transfer dough to a parchment-paper lined sheet pan. Form into a loaf about 12 inches (30 cm) long. Cover with plastic wrap and let proof another 2 hours.
Preheat oven to 450°F/232°C.
Remove plastic wrap and score dough as desired with a serrated knife or bread lame.
Bake 25 minutes, turning once halfway through.
Let cool on baking rack.