Put 1 cup of the milk in blender
container. Add spinach, a little at a time, blending until smooth after each addition.
In saucepan, melt butter. Stir in flour, salt, nutmeg and pepper. Cook over medium-low
heat until bubbly.
Stir in spinach mixture. Add remaining milk, yogurt, onion and chicken flavor
base. Cook, stirring constantly, over medium heat, until mixture begins to boil.
Reduce heat and simmer, stirring, for 2 minutes.