easy and yummy soup

Here's a supper idea that was quite easy. Use only things I always have around (spinach, potatoes, onions) and turn them into a meal! I made this easy soup and served it with some fresh tea biscuits (or scones, as they should be called) and a steamed piece of fish.

Cream of Spinach Soup
serves 4 to 6
adapted from Moosewood Restaurant Daily Special

2 T canola oil
1 T butter
2 c chopped onions
1/2 c chopped celery
salt
3 c chopped potatoes
2 1/2 c stock or water
300 g fresh spinach, washed
1 1/2 c milk (or evaporated milk, or half milk and half cream)
1/4 t nutmeg
salt and pepper

In a soup pot, warn the oil and butter. Add the onions and celery and sprinkle with salt. Cover and cook on low heat for about 10 minutes, stirring occasionally until the onions are soft and translucent.
Add the potatoes and stock or water, cover, and cook until potatoes are soft, about 10 minutes.
Stir in the spinach, cover, and set aside off the heat for 2 minutes, until spinach is wilted.
Puree the soup (in batches in a blender or using a hand immersion blender).
Stir in the milk, nutmeg, and season with salt and pepper. Reheat.
Serve with croutons, if desired.