Pistou: put the basil, peeled garlic, olive oil and some salt
and pepper into a liquidizer or food processor. Work the machine
until you have a fairly thick puree.
Sauce: slice the onions, cut the tomatoes into quarters and
put them with the onions into a saucepan on the stove. Add
100 ml (scant 1/4 pint) water, cook until the tomatoes have
softened to a pulp, sieve and set it aside.
Skin the salmon and bone it.
Cut each piece in two horizontally.
Arrange the fish in an oven dish smeared with olive oil. (the oven dish
needs to be made of a thin metal that conducts heat quickly.)
Season with salt, pepper and cayenne, and put a dab of butter
on to each piece of fish.
Pre-heat the oven to 200 oC/400 oF. Leave the salmon in the oven for
2 minutes, then take it out again.
It will continue to cook while you finish the sauces.
Reheat the tomato sauce. Season it with salt, pepper, cayenne and fresh
Bring it briefly to the boil.
The pistou can be eaten hot or cold; to heat it, whisk it while it
warms up over a low heat.
Serve each piece of salmon with a little tomato sauce underneath it.