Both the eating and cooking of brains require an emotional leap for the uninitiated if they are not to fall into the abyss of squeamishness.

On the other hand, if everyone realized how wonderful brains are, they would be far more expensive than they are now.

The best brains to buy are lamb or veal, but even beef brains are quite satisfactory. Just make sure they are fresh and use them within a day or two. s

Figure one set of brains for two people. While this makes for fairly small portions, remember that the dish is very rich and most people won't want a great deal. For four people, soak two pairs of brains in water acidulated with vinegar.

Rinse them off and them drop them into a saucepan of boiling water to which you have added 1/2 teaspoon of salt and another few tablespoons of vinegar. Drop them in gently as you would a poached egg and simmer for about 15 minutes, by which time they should be firm.

Drain the brains, rinse them with cold water and cut away the skin and veins. Divide them into slices about 1/2-inch thick.

In a large pan, fry 2 or 3 chopped cloves of garlic in a generous amount of butter (at least 2 tablespoons and more if you can bear to use it). Before either butter or garlic have a chance to brown, add 1/2 pound of fresh mushrooms, thinly sliced. Continue frying until mushrooms are soft, deep brown in color, and no longer give off any liquid.

Add the brains to the pan, cover and cook about 5 minutes, shaking the pan to ensure that all the favors are well blended.

The brains may be served as they are, with salt and pepper to taste, but a very welcome addition is a cup of lightly cooked fresh or frozen peas. The uncooked peas may be added before the brains and steamed for 3 or 4 minutes.

A small but sublime variation transforms the dish into a light creamy mixture which can be eaten as a main course or served in pastry shells for a first course. After the brains have been added, pour in about 1 cup of chicken soup. Homemade soup is preferable, but you may use very good quality canned soup.

When the mixture comes to the boil, remove it from the heat and add a little of the liquid to the beaten yolk of an egg. When the yolk is warm enough to prevent its curdling, add it to the pan, shake gently to mix and put it over a very low heat, being careful not to let the contents boil. Add one or two teaspoons of sherry, and let the pan stand for 10 minutes off the heat to enable the sauce to thicken.