Feed your sourdough starter 8-12 hours before mixing using a 1:1:1 ratio. It should double in size, be bubbly, and pass the float test.
Add water to mixing bowl, whisk in active starter until dissolved, then add flour and salt. Mix until you have a shaggy dough with no dry flour remaining.
Cover bowl and let rest 30-60 minutes at room temperature. This allows flour to absorb water and gluten to develop naturally.
With wet hands, grab one edge of dough and stretch up and over to opposite side. Rotate bowl and repeat 3 more times, then cover and rest 30 minutes.
Repeat stretch and fold process two more times, resting 30 minutes between each set. Dough should feel stronger and smoother after each set.
Let dough rise undisturbed in warm spot (75-80°F) for 3-4 hours until increased 50% in volume with smooth surface and visible bubbles on bottom and sides.
Turn dough onto lightly floured surface, fold edges toward center, flip over and drag in circular motion to create tension. Let rest 10-15 minutes.
Dust banneton with rice flour, flip dough seam-side up, perform final folds, and place in basket seam-side up. Cover and proof 1-2 hours at room temperature or refrigerate 30 minutes to 1 hour.
About 45 minutes before baking, preheat oven to 450°F (232°C) with Dutch oven and lid inside.
Turn dough onto parchment, score with one deep slash at 45-degree angle, and lower into hot Dutch oven. Bake covered 20 minutes, then uncovered 25-30 minutes until deep golden brown (205-210°F internal).
Remove bread from Dutch oven using parchment and transfer to cooling rack. Let cool at least 1 hour before slicing.