A little olive or sunflower oil
1 brown onion, sliced
300 g mushrooms
2 cups stock or water
a pinch of salt
1 medium potato
freshly ground black pepper
2 tablespoons chopped parsley
Brush a large saucepan with oil and sauté onion on medium heat for about 5 minutes without browning. Add mushrooms, increase heat and cook for 2 minutes. Add stock or water, season with salt and bring to a boil.
Peel, wash and dice potato. Add potato to soup and cook rapidly for 15 minutes. If necessary, add water during cooking to keep vegetables almost covered.
When cooked, blend to a puree. Reheat until just boiling and add extra liquid if necessary. Season with pepper and stir in parsley before serving. Serves 4.