Toasted Oat Soaker Four-Seed Country Boule

Steps

1. Day 1, about 9 a.m.: feed your sourdough starter with equal weights of extra all-purpose flour and extra water from your supply (not from the amounts listed) and leave it at about 75°F (24°C); it should double and peak, bubbly and domed, in 4 to 6 hours.
2. While the starter rises, make the soaker: toast 70 g of the oats (the soaker portion) with the pumpkin seeds and sesame seeds in a dry skillet over medium heat, stirring, for 5 to 6 minutes until golden and fragrant.
3. Tip the toasted oats, pumpkin seeds and sesame seeds into a bowl, stir in the ground flaxseed and the chia seeds, then pour in the 120 g soaker portion of the water. Stir and let it stand at least 1 hour until the liquid is absorbed and the mix is thick.
4. About 1 p.m.: in a large bowl, mix the all-purpose flour and the whole wheat flour with 300 g of the 330 g dough portion of the water until no dry patches remain. Cover and rest 45 minutes.
5. Add 100 g of the peaked sourdough starter and the molasses to the dough and squeeze them in with wet hands until even. Sprinkle the salt over the dough, add the remaining 30 g of the dough water, and pinch and fold until the water is absorbed. The dough is about 72% hydration and 2% salt (the soaker water is extra).
6. Rest 30 minutes, then spread the dough out in the bowl, add the oat and seed soaker and fold it in until the oats and seeds are evenly spread.
7. Bulk rise at about 75°F (24°C) for 4 to 5 hours. During the first 2 hours, do a set of stretch-and-folds every 30 minutes (4 sets), then leave it alone. Bulk is done when the dough has grown about 50 to 75%, feels airy and shows bubbles on the sides.
8. Turn the dough onto a bare counter, pre-shape into a loose round and rest 20 minutes uncovered.
9. Spread the remaining 20 g of the oats (the crust portion) on a plate. Shape the dough into a tight boule, mist or wet the top lightly, and roll the top in the oats to coat.
10. Set the boule oat side down in a banneton or towel-lined bowl lightly dusted with extra all-purpose flour, cover and refrigerate overnight, 12 to 14 hours.
11. Day 2: put a Dutch oven with its lid in the oven and preheat to 500°F (260°C) for 45 minutes.
12. Turn the cold boule out onto parchment, oat side up, and score it with one deep slash or a cross. Lower it into the hot Dutch oven, cover, and reduce the oven to 460°F (238°C). Bake 20 minutes.
13. Remove the lid and bake 25 to 30 minutes more, until the crust is deeply browned and the center reads 205 to 210°F (96 to 99°C).
14. Cool the loaf on a rack at least 2 hours before cutting into 12 slices.