Simmer broth, onion, carrots, salt, pepper and nutmeg in stockpot for 15 minutes.
Melt butter in saucepan over low heat; whisk in flour until smooth. Whisk milk into butter mixture, stirring constantly. Cook 2 minutes to create roux.
Stir roux into simmering soup base. Add spinach to soup and cook just to wilt (about 1 minute). Remove from heat and add cream and lemon zest.
Garnish with toasted almond slices, if desired.
NOTES: Instead of chicken stock I used vegetable stock made from vegetable base paste.
Source: Cuisine At Home January/February 2004