Heat the oil in a skillet over medium heat. Cook and stir the onion until tender.

In a saucepan, bring the water to a boil. Reduce heat to low, and dissolve the bouillon cube in the water.

In a blender or food processor, blend the onion, spinach, potatoes, nutmeg, and about 2 cups of the bouillon until thick and smooth.

Blend the potato mixture into the saucepan with the remaining bouillon. Bring to a boil, reduce heat, and simmer 20 minutes. Stir in the milk, and continue cooking 10 minutes. Season with salt, pepper, and more nutmeg to taste. Thus the soup is complete.