Jerusalem artichoke soup with wild mushrooms and hazelnuts
Instructions:
- Soup:
- 1 tablespoon white distilled or cider vinegar;
- 11⁄2 pounds well-scrubbed Jerusalem artichokes;
- 2 tablespoons butter;
- 1 cup chopped leeks (white and tender green parts), shallots, or sweet onion;
- 1⁄2 cup chopped celery or celery root;
- 31⁄2 to 4 cups chicken, duck, or light-colored vegetable stock;
- 1 teaspoon kosher salt;
- 8 ounces russet potatoes, peeled and cut into 1-inch chunks (about 11⁄2 cups);
- 1 small bay leaf;
- 2 teaspoons chopped fresh thyme;
- 3⁄4 cup half-and-half;
- 1 tablespoon Madeira, tawny port, or dry sherry;
- 1⁄2 teaspoon ground black pepper.
- Wild mushrooms and hazelnuts:
- 2 tablespoons butter;
- 8 ounces wild mushrooms, stemmed and cut into 1⁄4-inch slices;
- 1⁄4 cup peeled and finely diced Jerusalem artichokes;
- 1⁄4 cup shelled, skinned, and coarsely chopped hazelnuts;
- 2 tablespoons Madeira, tawny port, or dry sherry;
- 1⁄4 teaspoon freshly grated nutmeg;
- 1 teaspoon chopped fresh thyme;
- 1 tablespoon finely chopped flat-leaf parsley;
- Kosher salt and ground black pepper;
- Porcini oil or hazelnut oil, for drizzling (optional).
- For the soup:
- Fill a medium bowl with cool water and add the vinegar. (This acidulated water keeps the artichokes from oxidizing and darkening when cut.) Peel the artichokes only if the skins are blemished and cut them into thin slices, dropping them into the water as you go.
- Melt the butter in a large saucepan or small soup pot over medium heat. When the butter stops foaming, stir in the leeks and celery and a pinch of salt. Cook, stirring often, until the vegetables are soft, about 8 minutes. Stir in 31⁄2 cups of the stock and the salt and potatoes.
- Drain and quickly rinse the artichokes, then add them to the pot. Add the bay leaf and thyme. Bring to a boil, reduce the heat, and simmer partially covered until the artichokes and potatoes are very soft, about 30 minutes. Discard the bay leaf. Puree in a blender (working in batches to not fill the blender more than half full) and return to the pot, or puree the soup directly in the pot with an immersion blender. Stir in the half-and-half and Madeira. The soup should be very thick but not pasty, so add the rest of the stock or another splash of half-and-half if needed. Season with the pepper and more salt, if needed. Keep the soup warm over low heat, stirring occasionally.