For the Jerusalem artichoke soup with roasted pine nuts, put the lemon juice in a large enough bowl of cold water.
Peel the Jerusalem artichoke, cut into large pieces and add to the lemon water. Lightly saute the onion in butter in a large saucepan, covered, for 5 minutes. Dry the Jerusalem artichoke pieces.
Add to saucepan, cover and cook over medium heat for another 5 to 10 minutes. Stir from time to time. Vegetables should not brown. Add clear soup and milk.
Simmer the soup gently for 20 to half an hour without a lid, until the Jerusalem artichokes are tender. Puree the soup, then pass it through a sieve. Season with nutmeg, salt and pepper.
Briefly toast the pine nuts in a pan without fat.
Heat the soup again slightly without boiling it. Arrange the Jerusalem artichoke soup with roasted pine nuts and serve.
Preparation Tip:
Jerusalem artichoke soup with roasted pine nuts can also be prepared with vegetable milk.