Honey Pepper Feta Walnut Rye Boule

Steps

1. Day 1, 8 am: feed your sourdough starter its usual meal of equal weights of fresh grain and water, and leave it at about 75°F (24°C). It should double and peak, domed and bubbly, in 4 to 6 hours.
2. While the starter rises, heat the oven to 350°F (175°C), toast the walnuts on a tray for 8 to 10 minutes until fragrant, cool, then chop roughly. Crumble the feta and keep it in the fridge so it stays in distinct pieces.
3. About 1 pm, when the starter peaks: in a large bowl, stir the honey into the water until dissolved, then whisk in the sourdough starter.
4. Add 320 g of the rye flour (keep the remaining 10 g of rye flour for dusting), all of the bread flour, the salt and the black pepper. Mix with a wet hand or stiff spatula until no dry patches remain; the dough will be sticky and paste-like, which is normal for a rye-heavy loaf. This is about 74% hydration and 1.6% salt on the rye flour plus bread flour (about 77% hydration counting the starter), kept lower in salt because of the feta.
5. Cover and rest 30 minutes at about 75°F (24°C).
6. Bulk rise, about 4 hours at 75°F (24°C): with wet hands, do a set of stretch-and-folds, scattering in the walnuts and the feta and folding them through. Do two more gentle sets 30 minutes apart, then leave the dough covered and undisturbed. Bulk is done when the dough has grown about 50%, looks puffy and shows bubbles on the sides.
7. Shaping: dust a banneton or a towel-lined bowl with the reserved 10 g of rye flour. Tip the dough onto a lightly wet counter, fold the edges into the center, and with wet hands gently round it into a tight boule. Place it seam side up in the banneton.
8. Cold proof: cover and refrigerate overnight, 12 to 14 hours. It is ready when it has risen slightly and a fingertip pressed in leaves a dent that springs back slowly.
9. Day 2: put a Dutch oven with its lid in the oven and preheat to 475°F (245°C) for 45 minutes.
10. Turn the cold dough onto parchment, score a cross or a single deep slash, and lower it into the hot Dutch oven. Cover and bake 25 minutes.
11. Remove the lid, lower the heat to 450°F (230°C) and bake 20 to 25 minutes more, until the crust is deep brown and crisp and the center reads 205 to 210°F (96 to 99°C).
12. Cool the loaf on a rack for at least 2 hours before slicing so the rye crumb sets, then cut into 12 slices.