Cream of Any Green Soup

I hosted a soup party in November -- a soup kitchen of sorts. Here's the recipe for asparagus soup that my brother prepared, as well as the cover of the recipe book (which I borrowed from Amazon):

Cream of Any Green Soup
(serves six)

1 tbsp oil
1/2 cup onion, chopped
4 cups chicken stock
1/4 cup butter/margarine
1/4 cup flour
1/2 tsp salt
1/4 tsp white pepper
3 cups milk or half and half

1. Heat oil in large saucepan and saute onion over medium-low heat until soft but not brown, about 5 minutes. Add chicken stock, vegetables and appropriate seasonings. Simmer over medium heat until vegetables are tender. (Timing will vary depending upon the vegetable. Broccoli and cauliflower will take longer than asparagus, peas, artichokes and spinach.) When vegetables are soft, place about 1/3 of the soup mixture in a blender or processor with metal blade inserted and process until mixture is smooth. Repeat with remaining soup until all is pureed. Stir in appropriate cheese or ham, cover and set aside.
2. Melt butter in a heavy, 8-quart pot over medium-low heat. Slowly blend in flour, salt and white pepper. Cook, stirring to form a smooth paste, just until mixture starts to turn golden. Add milk slowly, stirring constantly. Cook until mixture thickens. Add vegetable puree and cook, stirring, until heated through.
3. Ladle soup into bowls, garnish and serve immediately.

Options

Artichoke
2 1/4 cups artichoke hearts, rinsed
chopped parsley for garnish

Asparagus
5 cups asparagus, cut into 1-inch pieces
1 1/2 tsp lemon juice
1/4 tsp tarragon leaves, crumbed

Broccoli
5 cups broccoli florets
1 tsp thyme, crumbled
1/2 cup Gruyere cheese, grated
Additional Gruyere for garnish

Cauliflower
5 cups cauliflower florets
3/4 tsp curry
1 cup cheddar cheese, shredded
chopped chives for garnish

Pea
4 cups fresh or frozen peas
1/4 cup shredded lettuce
1 1/4 cups cooked ham, diced
chopped chives for garnish

Spinach
6 cups spinach leaves, packed
1/4 tsp nutmeg
chopped chives for garnish