For the soup:
2 tablespoons unsalted butter
2 large leeks, white and pale green parts only, finely chopped
2 garlic cloves, smashed
1 (3-pound) winter squash such as kobucha, butternut, or pumpkin
1 quart chicken stock or low-sodium chicken broth
2 cups water
2 tablespoons light brown sugar (optional)
1 teaspoon fine sea salt
3/4 teaspoon finely ground black pepper
1/3 cup heavy cream
For the quick pickles:
1/2 cup apple cider vinegar
1/4 cup water
3 tablespoons sugar
2 teaspoons fine sea salt
1 tablespoon extra-virgin olive oil
1/2 cup cilantro leaves
1/2 teaspoon dried red pepper flakes
Make the soup: Peel and seed squash, then cut into 2-inch chunks, reserving about 1/4 pound for the quick pickles.
Heat butter in a large heavy pot over medium heat until hot. Stir in leeks and garlic and cook, stirring occasionally, until leeks are translucent, about 6 minutes. Stir in squash, stock, water, salt and pepper and bring to a boil. Cook soup, uncovered, until squash is very tender, about 25 minutes.
Transfer soup to a blender and puree in batches with cream. Season with sugar (if using), salt, and pepper to taste.
Make the quick pickles: Slice reserved squash as thinly as possible with a slicer or sharp knife. Heat vinegar, water, sugar, and salt in a saucepan over medium heat until sugar is dissolved. Pour vinegar mixture over squash in a bowl and let stand 15 minutes. Drain squash then toss with oil, cilantro, and pepper flakes. Serve soup topped with quick pickles.
Photo: Ian Knauer