This soup from southern Tuscany is quintessentially autumn, starring two of the season’s most representative ingredients: chestnuts and mushrooms. I picked it from the very traditional menu of a trattoria in Monte Amiata, an ancient and now dormant volcano that dominates the surrounding landscapes: the Val d’Orcia, Bolsena lake, the Chianti hills, and the Maremma plains.
It was cold outside, and we had just had a walk around Piancastagnaio, a town famous for its tile-roofed houses, clinging to the side of a cliff, and its ancient chestnut trees, after which it is named. The trees surround the town and gift the villagers one of the most important ingredients of their local cuisine—chestnuts—celebrated every year in the famous Crastatone festival. That soup, combining chestnuts with potatoes and porcini mushrooms, another prized local product, was screaming my name.
Since that day, I’ve made this soup often, with fresh porcini when I am lucky enough to find them at the market, or with frozen ones. Should you use frozen ones, don’t thaw them first; just simmer the soup a bit longer until they’re completely cooked. If you can’t find either, use whatever mushrooms are available.
This is a perfect soup for a weeknight meal, as you can prepare it in less than one hour.
- 1/4 cup extra-virgin olive oil, plus more for drizzling
- 2 shallots, finely sliced
- 2 pounds white potatoes, peeled and diced
- 2 bay leaves, fresh or dried
- 4 1/4 cups warm water
- 10 1/2 ounces porcini mushrooms, brushed clean and chopped
- 3 1/2 ounces pre-cooked chestnuts
- Fine sea salt
- Freshly ground black pepper
- Fresh parsley, finely minced
Cover the bottom of a pot with extra-virgin olive oil. Add the shallots and cook over low heat until soft.
Add the diced potatoes and bay leaves, stir, and cook over low heat for about 5 minutes. Pour in the water to cover the potatoes, lightly salt the water, and cook over medium heat, stirring occasionally, until soft, about 25 minutes.
Add the porcini mushrooms and cook for 5 more minutes.
When the mushrooms are soft, set aside a few chestnuts, then crumble the rest into the pot. Cook for 5 more minutes, stirring once in a while, until the soup is thick and creamy. You should be able to easily mash the potatoes against the sides of the pot with a wooden spoon. Taste and adjust the seasoning with salt and pepper.
Serve the soup topped with the reserved crumbled chestnuts, chopped parsley, and freshly ground black pepper. Finish with a drizzle of extra-virgin olive oil, which, warmed by the heat of the soup, will diffuse its grassy aroma and make the soup even tastier.