Roasted Chestnut Bisque

Name: Roasted Chestnut Bisque
Ingredients: The Bisque; 1 medium onion; 2 carrots; 3 celery stalks; 1 medium leek; 1/4 cup olive oil; 6 tablespoons cognac or brandy; 4 cups chicken stock; 2 7.4 ounce jars roasted and peeled chestnuts; 6-7 sprigs marjoram; 1 1/2 cups heavy cream; salt and pepper to taste; Marjoram Oil; 6 tablespoons olive oil; 4 sprigs marjoram