2½ lb. Delicata squash, halved lengthwise, seeds removed
2½ Tbsp. unsalted butter
2 large leeks, white and tender green parts, chopped
½ tsp. dried thyme
2½ cups vegetable or chicken broth
¾ tsp. salt
½ tsp. freshly ground pepper
Sour cream, for garnish
Preheat oven to 350 degrees. Place the squash, cut side down, on a baking sheet and bake until tender, about 40 minutes. Let cool slightly and gently scrape or cut the flesh away from the skin. Set aside.
Melt the butter in a saucepan over low heat. Add the leeks and thyme and stir occasionally until soft and brown, 10 to 15 minutes. Stir in the stock and the squash and simmer over medium heat for 20 minutes.
Using a blender (note, an immersion hand blender probably cannot handle the leeks), purée the soup directly in the pot until smooth. (Alternately, purée the soup in batches in a standard blender or food processor.)
Season with the salt and pepper. Ladle hot soup into individual bowls, then top with sour cream.