Watercress Soup

This makes an excellent starter, which is how I serve it tonight. It might be difficult to bulk this out to a full meal, so just serve first and enjoy. Even if you don't like watercress raw, this is a delicious soup; the spiciness of the cress dims immediately on cooking, leaving an earthy, savoury yet springlike taste.

Ingredients:

• 1 small onion
• 1 small potato
• 300ml hot stock (bouillon is fine)
• 1 bunch of watercress

Finely chop the onion and sweat in olive oil or butter over a low heat for 8 minutes, until transparent. Meanwhile, finely cube the potato, then add to the pan and allow to colour, stirring every so often so it doesn't stick. It's fine if a layer of golden starch builds up on the bottom of the pan, just don't let anything burn.

Pour in the hot stock and scrape the pan to deglaze it, then cover and simmer. Meanwhile, shred the watercress - Delia likes to use only the leaves, but I have found no problem including the stalks, if shredded finely. When the potatoes are just tender, add the watercress, stir once, replace the lid, and continue to simmer for 2-3 minutes until the leaves have wilted and the colour of the stalks has brightened.

Remove from the heat and blend thoroughly using an electric blender. Remove any stringy bits if they refuse to blend. Serve with a dollop of crème fraîche and a grating of black pepper.