Cream of ....[any Vegetable] Soup (dairy-free)

This recipe is great if you have lots of a certain vegetable, but don't know how to use it all up. I frequently do it with celery, asparagus, and zucchini.

2 medium onions or leeks, diced
2 celery, diced (opt.)
2 T butter
2-5 c main big vegetable (asparagus, zucchini, etc.)
2 quarts stock
sea salt and ground pepper, to taste

1. Melt butter in a large pot and add onions, celery and main big vegetable.
2. Add stock, cover and cook at least 30 minutes.
3. Puree soup with a handheld blender just till blended some; season to taste.

Variations:
celery base: ham, potatoes and peas (add cubed potatoes and simmer 30 minutes, then add ham and peas)
asparagus base: same as above
zucchini base: add corn and black beans?

Creamier taste w/o dairy: If you want to make this creamier, then blend ¼ cup of light olive oil 2 tsp nutritional flakes (cheesy/nutty tasting) and 2 tsp salt (or to taste) and add to the soup. The whipping of the oil makes it creamy.