Number Three Son, who last appeared in these pages saving a Costa Rican beach restaurant from gastronomical catastrophe, now emerges as cook and skivvy for an ex-hippie caff in the Haight-Ashbury district of San Francisco, an eatery where food-correctness rules supreme. He is also an apprentice barman. All very sensible, if one is fated to become, eventually, a restaurateur: learn the business from the bottom up.

Out in California, his speciality has been soups - hundreds, he says - and in passing on a few of his recipes, he noted that translating 'a San Quentin-sized cauldron of soup' into something for a polite dinner party is no easy task.

He does not claim originality for the three soups that follow: two come from the cookbook of that famous New York vegetarian restaurant, Moosewood (but, as he says, 'You and I both have a healthy irreverence for cookbooks'); and the third is derived from Julia Child ('seen on television, but not heard because I was cleaning my room'). But knowing him, I guarantee that the departures are more significant than the original recipes. Here are the soups: all for six people.

Hungarian mushroom soup

Ingredients: 1/4 lb (115g) butter

2 medium-sized onions, finely chopped

2lb (900g) mushrooms, thinly sliced

1tbs mild Hungarian paprika

2-3tbs fresh, or 1tbs dried, dill

3tsp lemon juice

1/4 lb (115g) all-purpose flour

1 pint (570ml) water or stock

1/2 pint (285ml) milk

1/2 pint (285ml) sour cream

fresh dill sprigs, softened butter

Preparation: Sweat onions in butter for 4-5 mins. Add mushrooms, dill, paprika and salt. Lower heat and cook for 15 mins. Add lemon juice, then flour, stirring constantly until flour turns nut-brown. Add water or light stock gradually, continuing to stir until ingredients blend. Lower heat and simmer 10- 15 mins. Remove from heat. Stir in milk and season to taste. Add a little soup to sour cream, whisk and blend with the rest of soup. Serve with warm bread and dill butter.

To make dill butter, chop fresh dill and mix with softened butter. Roll into sausage shape in foil by twisting ends in opposite directions. Chill and slice. Yam with yellow split-pea soup

Ingredients: 2tbs vegetable oil

1 large yellow onion

1 green chilli

1tsp cumin

1/2 tsp turmeric

1/2 tsp cinnamon

1tbs freshly grated ginger

2 pints (1 litre) cold water

2 large yams or sweet potatoes

1lb (450g) yellow split peas

1/2 pint (285ml) yoghurt

zest of 1 lime

fresh coriander

Preparation: Sweat onions and chilli in oil for 5 mins. Add ginger and other spices, then cold water. Add yams and split peas, bring to boil. Reduce heat and simmer for 90 mins. Remove half the soup, blend and return; add a little soup to yoghurt, whisk, then blend back into soup. Serve with fresh coriander and julienned zest of lime.

Roasted bell pepper soup

This is an old family favourite. Two soups can be made simultaneously: one with red peppers, the other with yellow or green. The two are ladled slowly side by side into a soup plate, with spectacular effect.

Ingredients: 3 bell peppers (red or green or yellow)

1/4 lb (115g) butter

2 medium-sized yellow onions

2 large, peeled potatoes

1 green chilli, chopped

2 pints (1 litre) chicken stock

2 bay leaves

1/2 tsp oregano

1/2 tsp thyme

1/2 tsp cayenne pepper

salt and pepper to taste

saffron, fresh coriander

Preparation: Roast peppers under grill until skin is charred and blistered; transfer to paper bag and leave to steam for 5 mins; wash with cold water so that skin peels off, and remove seeds. Set a small piece aside for garnish. Coarse- chop onions, saute in butter until dark gold; dice peppers and potatoes and cook for 5 mins. Add herbs, chopped chilli, cayenne, salt and pepper, then stock. Bring to boil, then simmer for about 45 mins or until potatoes break up. Reserve liquid, blend solids until smooth and add liquid to desired consistency. Garnish with coriander, julienned pepper and a few strands of saffron.

Number Three Son says he has hundreds more, but the soups here, he rightly claims, have made him 'something of a celebrity in the bisque business'. I would only add that soups are, when carefully conceived, splendidly nourishing and tasty meals-in-themselves for summer days, and what follows them - if anything is needed beyond a salad and some choice cheeses - should be kept simple.

If any reader should visit San Francisco, the place is called the Cafe International. I mention this not out of family pride, but because Number Three Son demonstrates, to my mind, what a good cook does. It is rather like a puzzle: faced with a stub of gorgonzola, some left- over green beans, a few pieces of roast chicken and some doubtful- looking vegetables, make a meal. Good cooks can do it; he can do it.

Good cooking starts with what is to hand and comprises equal portions of ingenuity, innovation, application and experience. All of these soups began with an idea, were experimented with for some time, tested on customers and refined. As almost anything can go into soups, they are laboratories for culinary experiment: they are, therefore, virtually foolproof for the inexperienced cook.