Overnight Poolish Spelt Sandwich Loaf

Steps

1. The night before (12 to 14 hours ahead), make the poolish: in a medium bowl, stir together 200 g of the spelt flour, 200 g of the water and 1 g of the instant yeast until no dry spelt flour remains. Cover and leave at about 75°F (24°C) for 12 to 14 hours, until bubbly, domed and just starting to sink in the center.
2. Next day, make the dough: in a large bowl, whisk the remaining 160 g of water with the molasses, then stir in the poolish to loosen it.
3. Add the remaining 250 g of spelt flour, 40 g of the bread flour, the remaining 4 g of instant yeast and the salt. Mix into a shaggy dough, then rest 10 minutes.
4. Add 10 g of the olive oil and knead 4 to 5 minutes, just until smooth and slightly tacky; spelt gluten is delicate, so don't overknead. The dough is about 72% hydration and 2% salt.
5. Cover and let rise at about 75°F (24°C) for 60 to 75 minutes, until about one and a half times its size and puffy; spelt rises quickly, so watch the dough, not the clock.
6. Brush a 9x5-inch loaf pan with the remaining 5 g of olive oil.
7. Dust the counter with the remaining 10 g of bread flour. Turn the dough onto it, press into a rectangle, roll it up tightly from the short end, pinch the seam and set it seam-side down in the pan.
8. Cover and proof at about 75°F (24°C) for 35 to 45 minutes, until the dough crowns about 1 inch above the rim and springs back slowly when poked. Meanwhile, preheat the oven to 425°F (220°C) with a rack in the lower middle.
9. Slash the top lengthwise and bake 15 minutes, then lower the oven to 400°F (200°C) and bake 15 minutes more.
10. For a crisp crust, turn the loaf out of the pan and set it directly on the oven rack for 5 to 8 more minutes, until deep golden all over and the center reads 200–205°F (93–96°C).
11. Cool the loaf on a rack for at least 2 hours before slicing into 12 slices.