Place stock in a saucepan together with onion, carrot, salt, pepper and nutmeg and bring to a boil over low heat for 15 minutes.
Melt butter in another saucepan over low heat and stir in flour. Remove pan from the heat and gradually add milk stirring vigorously.
Bring to a boil and lower heat. Add simmering stock with vegetables. Combine, add spinach and cook for 1 minute. Remove from heat and add cream and lemon peel.
Serve immediately and garnish with browned sliced almonds.