Spring vegetable soup

The farmers market has an abundance of farm fresh organic Asparagus.
I always get my inspiration from seeing all the wonderful fresh produce.
Try this delicious vegetable soup. It is quick and easy. Everything is going to be puréed, so you can give everything a rough chop.

2 Tbsp. Olive oil
1 small onion
The stems from 2 bunches of asparagus, cut off an inch at the ends. Tips reserved.
1 white sweet potato
3 stalks of celery
4 - 5 cups of vegetable stock
1 tsp salt, pepper

Heat the oil in a medium size pot. Add the onion and cook for 6 minutes, until it is has softened.
Add the asparagus stems, the celery and the potato. Stir. Add the stock. Bring to a boil, reduce to a simmer and cook for 30 minutes. Remove from the stove. In small batches purée the soup with ½ cup of liquid at a time. Transfer to another pot or bowl. Add just enough of your leftover stock to form the consistency of the soup. It should not be too thin. Remember you can always add liquid but it is very hard to take out.
Then transfer all to a pot. Add the asparagus tips and simmer for 5 minutes.
Add the salt and a little pepper. Season to taste.