Asparagus Soup

This soup is very creamy, but totally low fat.

2 cups fresh asparagus, cut into 1 inch pieces
3 cups broth
1 medium Yukon gold potato or half a russet, peeled
1/2 onion, chopped
4 cloves garlic
1/4 c nonfat milk (you can use cream or half and half, but it will increase the fat content, of course)
1/4 tsp cayenne pepper
salt and black pepper to taste

In a large pot, bring broth to a boil. Add asparagus, potato, onion, and garlic and reduce to medium heat. Cook until asparagus and potato is soft. Using an immersion blender or a food processor or blender, puree broth and vegetables until smooth. Bring to a boil again. Stir in milk, cayenne pepper, and add salt and black pepper as needed.