Butternut Squash Soup with Gruyère Pesto

The generic recipe for winter squash soup or puree typically begins by calling for a scary amount of the squash “peeled, seeded, and cubed,” and then steamed or boiled. Have you ever tried to peel, let alone cut, even one of these hard winter squashes? There may be no easier way to cut yourself in the kitchen. And why bother boiling or steaming a vegetable, which makes it watery, when you can roast it and concentrate the flavor?

My favorite way to cook winter squash is to cut it in half lengthwise, scoop out the seeds (or not—they’re even easier to scoop out and discard after the squash is cooked), and bake it, cut side down, on a sheet pan in the oven. Now caramelized it is delicious straight up. But puree it and add other ingredients and it can go anywhere.

My Gruyere pesto isn’t really a classic pesto. I added some Gruyere to the standard recipe, left out the oil, and did not puree the mixture. But whatever you call it, my “pesto” adds a nice crunch and a fresh final touch.

This is a satisfying soup that freezes well. You can concoct alternative versions of it by flavoring it with fresh ginger and lime or garnishing it with sautéed apple, crispy bacon, and Cheddar or with crumbled blue cheese and toasted walnuts.

For the Soup:
2 medium butternut squash
2 tablespoons unsalted butter

2 medium leeks, white parts only, thinly sliced
1 quart chicken stock, preferably homemade, plus more as needed for thinning
Kosher salt and freshly ground black pepper to taste

For the pesto:
1/4 cup coarsely grated Gruyere cheese
2 tablespoons toasted pine nuts, coarsely chopped
1/4 cup packed fresh basil leaves, shredded
1 tablespoon freshly grated Parmigiano-Reggiano
Kosher salt and freshly ground black pepper to taste

Serves 4 to 6

To prepare the soup, preheat the oven to 375ºF. Halve the squash lengthwise, scoop out the seeds, and arrange cut side down on a lightly oiled baking sheet. Bake until very tender, 50 to 60 minutes. Cool to room temperature. When cool enough to handle, scrape out the pulp. You should have about 6 cups.

Heat the butter in a large soup pot or kettle over medium heat. Add the leeks and cook, stirring often, until softened, about 5 minutes. Add the squash and 1 quart of the chicken stock, increase the heat to high, and bring to a boil. Reduce the heat to medium high and simmer, stirring often, until the leeks are tender, about 10 minutes. Working in batches, puree the soup in a food processor or blender until smooth. Thin with additional stock as needed to reach the desired consistency. Return to the soup pot and season with salt and pepper.

To prepare the pesto combine the Gruyere, pine nuts, basil, Parmigiano-Reggiano, salt, and pepper in a small bowl. Keep at room temperature until ready to serve.

Serve the soup in warmed bowls. Garnish with a spoonful of the pesto just before serving.