1: Mix the dough: In a large bowl, whisk 350 grams water and 100 grams active sourdough starter together. Add 500 grams bread flour and 30 grams brown sugar. Mix until no dry flour remains. Cover and rest 30 minutes.

2: Add salt: Sprinkle 10 grams fine sea salt over the dough. Pinch and fold until fully worked in. Cover and rest 30 minutes.

3: Stretch and fold: Do 3 sets of stretch and folds, 90 minutes apart. Turn the bowl and fold each side into the middle each time.

4: Add cinnamon swirl and raisins: Mix 2 teaspoons ground cinnamon into 30 grams unsalted butter, softened to make a cinnamon butter. Toss 110 grams raisins in 1 tablespoons extra flour for tossing raisins. Press dough into a rectangle, spread on the cinnamon butter, and sprinkle with raisins. Roll and fold to seal them in.

5: Bulk ferment: Cover the dough and let it rise at room temperature until it grows by about 50%. This takes 4 to 270 minutes depending on how warm your kitchen is.

6: Shape the loaf: Turn the dough onto a lightly floured surface. Shape into a round or oval loaf. Place seam-side up in a floured banneton or bowl lined with a towel.

7: Cold retard overnight: Cover the banneton and place it in the fridge for 8 to 480 minutes. This builds flavor and makes the dough easier to score.

8: Preheat and score: Preheat your oven to 450°F (230°C) with a Dutch oven inside for 30 minutes . Turn the cold dough onto parchment paper. Score the top with a sharp blade.

9: Bake: Place the dough into the hot Dutch oven with the lid on. Bake 45 minutes covered, then remove the lid and bake 20 to 25 minutes more, until deep golden brown.

10: Cool completely: Move the loaf to a wire rack. Let it cool for at least 60 minutes before slicing. Cutting too early makes the inside gummy.