- 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
- ¼ cup coarsely grated Gruyere cheese
- 2 tablespoons toasted pine nuts, coarsely chopped
- ¼ cup packed fresh basil leaves, shredded
- 1 tablespoon freshly grated Parmigiano-Reggiano
- Kosher salt and freshly ground black pepper to taste
- To prepare the soup, preheat the oven to 375°F. 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 Gruyère, 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.