Ingredients:
350 grams(12 ounces) butternut squash, peeled
2 tablespoonsolive oil
1 teaspoonground cumin
1/2 teaspoonpaprika
1/2 teaspoonchile flakes
2 teaspoonsflaky sea salt
350 milliliters(12 fluid ounces, 1½ cups) buttermilk
250 grams(9 ounces, scant 2 cups) plain (all-purpose) flour, plus extra for dusting
250 grams(9 ounces, scant 2 cups) wholemeal (whole-wheat) flour
2 teaspoonsnigella (black onion) seeds, plus extra to finish
1 1/2 teaspoonsbicarbonate of soda (baking soda)
Directions:
Heat the oven to 210°C (190°C fan/400°F/gas mark 6).
Chop the butternut squash into 2-centimeter (¾-inch) chunks and place on a baking sheet.
Drizzle with the olive oil and add the cumin, paprika, chile flakes, and 1 teaspoon of the salt. Toss with your hands to make sure the squash is evenly coated in the spices.
Roast the squash for 25 to 30 minutes, turning halfway, until cooked through. Place the squash into a jug or bowl and mash with a fork. Pour in the buttermilk and stir to combine.
In a large bowl, mix together the flours, nigella seeds, bicarbonate of soda, and the remaining 1 teaspoon of salt. Pour in the buttermilk and squash mixture and stir with a table knife until you get a shaggy dough. Turn the dough out onto a lightly floured surface, give it just a couple of quick kneads to bring it together, and shape into a mound (or two, if making smaller loaves). You’re not trying to smooth it out, so try not to overwork it.
Dust a baking sheet with flour or line with baking paper. Place the dough onto the sheet and use a sharp knife to make a deep cross on top, about 4 centimeters (1½ inches) deep. Scatter a few more nigella seeds over the top and bake for 45 to 50 minutes until well risen and the base of the loaf sounds hollow when tapped. (If you’re making two smaller loaves, bake for 25 to 30 minutes.) Transfer to a wire rack and leave to cool before slicing.