In a mixing bowl, combine 500g all-purpose flour, 300g water, and 100g active sourdough starter until no dry flour remains.

Add 10g salt, 50g brown sugar, and 2 tablespoons ground cinnamon to the dough and mix until evenly distributed.

Turn the dough onto a lightly floured surface and knead for 10 minutes until smooth and elastic.

Place the dough in a lightly oiled bowl, cover, and let rise at room temperature for 6 to 12 hours.

Turn the dough onto a floured surface and shape into a round loaf.

Place shaped dough in a proofing basket, cover, and let rise for 1 to 2 hours until doubled in size.

Preheat oven to 450°F (232°C) with a Dutch oven inside for 30 minutes.

Carefully transfer dough to hot Dutch oven, score top, and bake covered for 30 minutes.

Remove lid and bake for an additional 10 to 15 minutes until crust is deep golden brown.

Let bread cool on a wire rack for at least 1 hour before slicing.