• 2 tablespoons olive oil
• 3 or 4 spring onions (scallions), chopped
• a couple of leafy celery stalks, chopped
• 250 g(9 oz) zucchini (courgettes), cut into blocks
• 400 g(14 oz) potatoes, peeled and cut into blocks
• 100 g(3½ oz) shelled peas
• 100 g(3½ oz) lettuce (romaine/cos or butter), shredded
• 50 g(1¾ oz) watercress tips, chopped
• 120 g(4¼ oz) baby english spinach, shredded
• 2 eggs
• juice of 1 large juicy lemon
• grated parmesan cheese, to serve

Heat the oil in a fairly large soup pot. Gently sauté the spring onions and celery until they have softened but not coloured, then add the zucchini, potatoes, peas and half of the lettuce and watercress.

Add 1.5 litres(52 fl oz/6 cups) of water, salt well and bring to the boil. Put the lid on, lower the heat and simmer for 30 minutes, or until the potatoes are soft. Add the remaining lettuce and watercress and the baby spinach and cook for 1 or 2 minutes more. Meanwhile, whip the eggs in a bowl and then whisk in the lemon juice and a pinch of salt. Take a ladleful of the hot broth from the soup and whisk it into the eggs to acclimatize them. Then add a couple more ladlefuls, whisking them in well.

Take the soup off the heat and tip all the egg mixture back into the pot, mixing all the time. Keep mixing, and put the pot back over the lowest possible heat for just a minute so the eggs cook through but don’t scramble. Taste for salt, and serve warm with a generous scattering of parmesan, more lemon juice to taste and a good grinding of black pepper, if you like it.