Nigella Lawson's Roast Squash and Sweet Potato Soup

Roast Squash and Sweet Potato Soup with Buttermilk-Blue Cheese Swirl

It may seem a bit fiddly to have a soup prepared in two parts: one in the oven; one in the pan. But I do this not only because I think it intensifies the flavor dramatically, but because it actually makes my life easier.

The thing is this: when you roast a butternut squash, you can go ahead and liquidize it without ever having to peel it (I found this out when I made the Butternut Orzotto on p. 134) and when I’m thigh-deep in cooking season, this is a real boon. Plus, I love the slightly flecked look that the spice-sized specks of skin give the soup, as well as the hint of texture.

The robust sweetness of this soup is countered by the buttermilk and blue cheese drizzling-mix that I swirl over the soup as I serve it and, indeed, I think it’s the two together that really make it.

-Preheat the oven to 400°F. Put the chopped onion, chopped butternut and sweet potato (again, don’t worry that neither of these last two are peeled) onto a cookie sheet.

-Drizzle the oil over them and sprinkle with the cinnamon and nutmeg, then roast in the oven for about 1 – 1 1/4 hours, by which time all should be tender. Remove from the oven.

-While the vegetables are still warm or at room temperature, liquidize them in a blender in 2 batches, adding 2 cups of vegetable broth to each batch.

-Pour the blended vegetables into a saucepan. Swish another 2 cups of vegetable broth in the blender to get out all the remnants of the soup, and pour into the pan. You have now added 1 1/2 quarts of liquid to the vegetables.

-On reheating to serve, add the marsala, and taste for seasoning. You may need to add up to another 2 cups of water if the soup’s too thick for your liking.

-As the soup warms up, liquidize the blue cheese and buttermilk in a clean blender and spoon into a jug or bowl.

-On serving, drizzle some of this mixture over each bowl. Leave the jug on the table for your guests to have some more if they wish.

Serves 8-10 as a starter, 6 as a main course

1 onion, peeled and roughly chopped

1 butternut squash (unpeeled), halved, seeded and sliced into 1 1/2 x 1-inch chunks

2 large (1 lb) sweet potatoes or yams (unpeeled), cut into 1-inch rings

1/4 cup olive oil

Teaspoon ground cinnamon

1/2 teaspoon ground nutmeg

1 1/2 quarts vegetable broth

1/2 cup marsala wine

Salt and pepper

For Serving:

1 cup crumbled blue cheese

1 cup buttermilk