Combine Dry Ingredients. In a large mixing bowl, thoroughly mix together 500 g of bread flour and 100 g of rolled oats until evenly distributed.

Prepare Wet Ingredients. In a separate bowl, combine 350 g of room temperature water, 100 g of active sourdough starter, and 50 g of honey, whisking until blended.

Mix Together. Pour the wet mixture into the dry ingredients and stir until a shaggy dough forms, ensuring no dry flour remains.

Add Optional Butter. If using, add 20 g of melted butter to the dough and mix until fully blended.

Autolyse. Cover the dough and rest for about 30 minutes to allow the flour to hydrate.

Incorporate Salt. Sprinkle 10 g of salt over the dough and stretch and fold several times to incorporate.

Stretch and Fold. Over the next two hours, perform stretch and folds at 30-minute intervals.

Shape the Dough. Shape the dough into a round ball and place it seam side up in a floured proofing basket.

Proof the Dough. Cover and let it proof at room temperature for 4 to 6 hours until risen and puffy.

Preheat the Oven. Preheat your oven to 450°F (230°C) and place a Dutch oven inside.

Score the Dough. Turn the dough onto parchment paper, score the top with a knife, and optionally sprinkle additional oats.

Bake in Dutch Oven. Carefully place the dough into the hot Dutch oven, cover, and bake for 30 minutes.

Finish Baking. Remove the lid and bake for an additional 15 to 20 minutes until golden brown.

Cool Before Slicing. Remove the bread from the oven and cool on a wire rack for at least 1 hour.