A silky, subtly sweet little number that makes fall vegetables feel downright swanky.
- 6 tablespoons unsalted butter, divided
- 1 large fennel bulb, thinly sliced
- 1 small onion, thinly sliced
- 2 carrots, peeled, chopped
- 1 small Yukon Gold potato, peeled, halved
- Kosher salt and freshly ground black pepper
- 4 cups low-sodium vegetable broth
- ¼ cup coarsely chopped roasted chestnuts from a jar
- 1 tablespoon pure maple syrup
Heat 4 Tbsp. butter in a large heavy pot over medium. Add fennel, onion, carrots, potato, thyme, and bay leaf; season with salt and pepper. Reduce heat to medium-low, cover, and cook, stirring occasionally and reducing heat if needed, until vegetables are soft but not browned and have released their moisture, 45–60 minutes (this will give them deep flavor).
Add broth, bring to a boil, and season with salt and pepper. Reduce heat and simmer until potato is falling apart, 8–10 minutes. Let cool slightly. Remove herbs.
Working in batches, purée in a blender until smooth. Strain into a clean pot; season with salt and pepper.
Heat remaining 2 Tbsp. butter in a small saucepan over medium. Add chestnuts and cook, stirring often, until butter is browned and chestnuts are toasted, about 4 minutes.
Mix crème fraîche and maple syrup in a small bowl. Serve soup topped with maple crème fraîche and chestnuts.
DO AHEAD: Soup can be made 3 days ahead. Cover and chill.