Delicious jerusalem artichoke and boletus soup

Do you know Jerusalem artichokes (topinambours in French)? They're roots, not very easy to peel with a very subtle taste of artichokes. They used to be eaten by French people during the second world war, as there was not much left to eat. That's why nobody ate them for decades. Bad souvenirs.
Yet, it's unfair, as there so good...

Serving 6, you need :

1kg of Jerusalem artichokes (1kg de topinambours)

1 box of dried boletus (1 petit bocal de cèpes séchées)

1 onion (1 oignon)

Chicken broth (1 bouillon de volaille)

10 cl of sour cream (10 cl de crème liquide)

Baking soda (bicarbonate de soude)

- Peel the jerusalem artichokes

- Put the dried boletus in warm water for 15 min then in boiling water for 10, then drain them

- Peel and slice the onion

- Fry the onion and the boletus for 5 min in one tablespoon of olive oil

- Add the Jerusalem artichokes, cover with water, add salt and pepper, some chicken broth (bouillon de volaille) and 1 tablespoon of baking soda (this helps make the Jerusalem artichokes easier to digest).

The best broth in France is Aryake. You can find it in many Monoprix now.

- Cook for 30 min and blend the soup with 10 cl of sour cream

Enjoy!!