01 - In a large mixing bowl, combine the sourdough starter, water, and brown sugar. Stir until the sugar has completely dissolved and the mixture is uniform.
02 - Add bread flour, whole wheat flour, cinnamon, nutmeg, ginger, and salt to the bowl. Mix thoroughly until a sticky, shaggy dough forms.
03 - Fold in the grated carrots, raisins, and nuts until evenly distributed throughout the dough.
04 - Knead the dough gently for 3-4 minutes by hand or with a dough hook attachment until just combined. Avoid overworking.
05 - Cover the bowl with a clean towel and let the dough rest for 30 minutes to allow hydration.
06 - Perform 3-4 sets of stretch and folds every 30 minutes over the next 2 hours to develop gluten structure. Grab one edge of the dough, stretch it upward, and fold it over the center. Rotate the bowl and repeat.
07 - Cover and let the dough rise at room temperature for 4-6 hours until it has doubled in size.
08 - Shape the dough into a round boule or oval batard. Place in a parchment-lined banneton or bowl.
09 - Cover and refrigerate overnight for 8-10 hours. This slow fermentation develops complex flavor and improves texture.
10 - Preheat the oven to 450°F with a Dutch oven inside to ensure proper heat retention.
11 - Turn the dough onto parchment paper. Sprinkle with oats and seeds if desired. Score the top of the loaf with a sharp knife or lame.
12 - Carefully transfer the dough into the preheated Dutch oven. Bake with the lid on for 25 minutes to create steam.
13 - Remove the lid and bake for an additional 20 minutes until the crust is deep golden brown and sounds hollow when tapped.
14 - Transfer the loaf to a wire rack and cool completely before slicing. This ensures proper crumb structure.