Soft Honey Walnut Peanut Whole Wheat Boule

Steps

1. Night before, about 10 PM: feed your sourdough starter from your own starter supply as usual, in equal weights, and leave it at about 75°F (24°C); it should peak, doubled and bubbly, in 8 to 12 hours.
2. Morning: toast the walnuts in a dry skillet over medium heat for 4 to 5 minutes until fragrant, let them cool, then chop the walnuts and the peanuts roughly.
3. In a large bowl, mix the whole wheat flour and the bread flour with 300 g of the water and all of the milk until nothing dry remains. Cover and rest 45 minutes (autolyse).
4. Add the sourdough starter, the honey and 10 g of the softened butter (half). Squeeze and fold until combined, about 3 minutes.
5. Sprinkle the salt over the dough with the remaining 30 g of the water and squeeze it in until fully absorbed. Measured against the combined whole wheat flour and bread flour, the dough is about 78% hydration (water plus milk) and 2% salt.
6. Bulk rise at about 75°F (24°C) for 4 to 5 hours, doing 4 sets of stretch-and-folds 30 minutes apart; spread the walnuts and peanuts over the dough during the first set and fold them in.
7. Bulk is done when the dough has risen about 50%, looks domed and airy, and jiggles when the bowl is shaken.
8. Turn the dough onto a lightly dampened counter, pre-shape it into a round, and rest 20 minutes. Shape a tight boule and place it seam-side up in a bowl lined with a lightly oiled piece of parchment.
9. Cover and cold-proof the boule in the fridge for 10 to 14 hours overnight.
10. Next morning, place the Dutch oven with its lid in the oven and preheat to 450°F (230°C) for 45 minutes.
11. Turn the boule onto a fresh sheet of parchment, score the top, and lower it into the hot Dutch oven. Bake covered for 25 minutes.
12. Uncover, lower the oven to 400°F (205°C), and bake 15 to 20 minutes more until deep brown and 205°F (96°C) in the center.
13. Right out of the oven, brush the crust with the remaining 10 g of the butter (the other half), then cover the loaf loosely with a clean towel to soften the crust.
14. Cool the loaf on a rack at least 2 hours before cutting it into 12 slices.