This is an era of plush custom kitchens, in which expensive cooking equipment is worshipped as idols once were. So it is easy to forget that cooking, like religion, can be practiced almost anywhere and even a complex meal can be crafted in a simple setting; that the taste of what is being served is more important than the pedigree of the pan.

A witness to the doctrine of simplicity in the kitchen is Alfredo Viazzi, whose impressionist recreations of recipes of his native Italy keep two Greenwich Village restaurants-Trattoria da Alfredo and Tavola da Alfredo-full to overflowing. Most of the dishes he introduces are perfected in his home, but not without some effort. "To cook in my kitchen, you must be patient and courageous. It's typical of New York, like a closet, with an electric stove, which I hate. So I look on it as a challenge."

Viazzi is a man with the charm of a Renaissance troubador, but he uses food rather than music to entertain. His most recent successes in New York (there was another restaurant in the 1950s, Portofino) are rooted in two precepts: being natural (eschewing pretension in either setting or sauces and offering foods that taste like themselves) and making a fetish of freshness. It is no surprise that critic Gael Greene took Paul Bocuse and a trio of his fellow nouvelle cuisine chefs to dine at Trattoria da Alfredo. Even if they couldn't read the menu, they could sense a kindred spirit.

I've often felt, however, that while French chefs were arguing about the proper "structure" of a recipe, Italian chefs would have taken the same ingredients, cooked the dish and served it. It is this impromptu, free-form approach that makes much of the repertory of Italian cooking-not just spaghetti-adaptable to American kitchens.

"There is no natural haute cuisine in Italy," Viazzi said during a recent visit to prompt his new book, "Alfredo Viazzi's Italian Cooking" (Random House, $10.) "Italy is a regional kitchen. You go from one area to another and the food is totally different. My kind of cooking favors the north, where I grew up, but it goes from one end to the other. I might do a dish from Emilia-Romagna, but I won't hesitate to substitute a different cheese, a different pasta or change the sauce. You can't be dogmatic." In this vein, he favors freshness over authenticity and will substitute in a recipe rather than use inferior or preserved vegetables and fruits. (Canned plum tomatoes are an exception, however.)

He feels part of the hangup with Italian cooking here is due to the limited exposure it has been given in restaurants. "Most of the cooks were Southern Italians, and many of them had learned here, not in Italy. They overcooked fish and vegetables, fried everything, relied on tomato sauce and used spaghetti as a garnish. Others feared Americans would not eat real Italian food, so they called their restaurants 'continental' which meant they wished to be thought of as French.

"When I opened the Trattoria eight years ago, I decided to make the kind of dishes chefs cook for themselves after work and the food of the trattorias I knew as a boy. I served pasta with vegetable sauce. I used cream and butter not olive oil, to make sauces. I served vegetables as a course, not just as a garnish and didn't overcook them. I didn't fry fish."

What he did do was to behave in the restaurant exactly as he does at home.(The Trattoria too, has a tiny kitchen, which limits storage. For that reason, he doesn't sell wine. Customers bring their own or buy it at a liquor store next door.) Groceries arrive daily from some of the best retail shops in Greenwich Village. "I pay more," Viazzi said, "but they but the best and I get the best of what they get." Daily specials, usually four, are added to the menu only after the shopping is done. "If Balducci (the much admired Italian grocery on 6th Avenue) receives a shipment of fresh wild mushrooms, they call me and I'll be serving them that evening."

Viazzi has succeeded big bt staying small. His Trattoria seats only 38. Tavola Calda's capacity is 45. They do three or more turns (seatings) a night to provide necessary volume. The Trattoria, shaped like a piece of pie on a corner, has an unadorned floor and utilizes hanging plants in place of store-bought decor Tavola Calda, based on the Italian version of a fast-food carryout, features a variety of dishes that are prepared in advance or need only brief heating.

About 150 of the recipes he has used there-either improvised or collected on his travels-are included in the book. Most have introductions explaining their derivation, but the editors haven't stepped in to help the convenience-oriented cook. There are no short cuts or hints for what to prepare ahead.

One reason, Viazzi explained, is that the recipes mirror his own approach to cooking. He has a fine collection of cookware ("built up slowly over the years; I buy something when I need it, not just to own it"). It includes some modern electrical aids, but he doesn't use them very often. When he plans to cook, he explained, he seldom hires help or prepares in advance.

"I just get up and do it," he said. "I clean up as I go. My kitchen demands that, and I invite as many as can fit to come into the kitchen with me. We stay until it's done. You shouldn't compromise on time, or on ingredients if you want to cook well. Of course many Italian dishes can be done quickly and you can prepare sauces and other things ahead. Homemade pasta is so quick to cook, only 1 1/2 or 2 minutes. That's why it's difficult. Add anything. I use fish with long noodles or with rice. Use leftovers. Rice (risotto) is easy. They don't do it often in restaurants because it needs attention, but at home in 35 minutes you can make a great one-dish meal."

Viazzi's recipes also are unorthodox. Some of them contain very un-Italian ingredients such as A-1 sauce. "They are," he said with a shrug, "what has worked for me." Make them in the spirit, not just the letter, of their author, he might add. He suggests that in the introduction to his book, when he quotes a woman, on leaving the Trattoria, as saying to him, "Ah, now we must go back to the United States."

Perhaps the following will transport you, not in Italy, at least to Greenwich Village.

ZUPPA DI COZZE

(Mussel Soup)

(6 servings) 1/2 cup olive oil 1/2 small onion, finely sliced 1/2 teaspoon chopped garlic 4 tablespoons dry white wine Salt 1/2 pound fish heads and bones 1/2 tablespoon chopped parsley Pinch oregano Pinch thyme Pinch nutmeg 4 or 5 leaves fresh tarragon or 1/2 teaspoon dried tarragon 1/4 teaspoon pepper 4 pounds mussel, thoroughly cleaned in cold water 4 tablespoons butter 1 envelope saffron 1 lemon, cut in 6 sections Croutons (optional)

Heat oil in a large soup pot and cook onion until translucent. Add garlic and cook until golden. Add wine and let it cook until it evaporates. Add 6 cups water, 1 1/2 teaspoons salt and bring to a boil. Put in fish heads and bones. Place all herbs in small cheesecloth bag together with nutmeg and pepper, and immerse bag in water, with one end tied to the handle of the pot. Cook 25 minutes.

Meanwhile, place mussels in a pot large enough to accommodate them comfortably. Add 2 cups of water and steam until mussels open. Allow to cool, then scoop out carefully. Place in dish, and set aside.

Strain fish stock through a fine wire strainer, lined with 2 layers of cheesecloth to make certain that no bones go through. Discard bag of herbs. Put clear broth back on flame and add the butter. Let butter melt as the broth comes to a boil. Add mussels and saffron. Cook 5 minutes.

Serve hot with lemon sections. You can also serve it with croutons.

PEPERONI STILE BIFFI

(Stuffed Peppers Biffi)

6 servings)

II Ristorante Biffi has been located in the Galleria Vittorio Emanuele in Milan since the latter part of the nineteenth century. Until the 1950s it was a first-class restaurant, and its patrons were the glittering superstars of the nearby La Scala, eminent composers, writers, movie directors, the beautiful soubrettes of the varieta houses and the inevitable motley groups of hangers on.

The menu always featured a most elaborate buffet that included Peperoni Stile Biffi. Unfortunately, Biffi's has now been converted into a sort of self-service restaurant, featuring such fare as pizza, hot dogs and packaged potato chips. The famous peperoni are no longer to be found, but their memory is well worth preserving. 1/4 loaf Italian bread, in rough hunks 1 pint heavy cream 6 medium-to-large sweet red peppers (or green, if red are not available) 8 filets of anchovies 3 pieces canned whole red pimiento 1/4 cup medium-sized capers 1/2 cup chopped parsley 3 cans (3 1/2 ounes each)(Genova tuna, Flaked, undrained (drain if using American tuna) 1/2 cup pitted black olives, roughly chopped Pinch oregano Pinch nutmeg pepper to taste 1 cup grated parmesan cheese 1/4 cup olive oil 1 cup beef or chicken consomme

Soak bread in cream. Cut off tops of peppers and clean insides of all seeds and fibers; shave bottoms slightly so that peppers will stand up in baking pan. Wash peppers well under running cold water. Dry.

Prepare stuffing: coarsely grind anchovies, pimiento, capers and soaked bread. Place mixture in mixing bowl and add parsley, tuna, olives, oregano, nutmeg, pepper and all but 4 tablespoons of the cheese. Mix throughly, then stuff peppers with mixture.

Put olive oil and consomme in a deep baking pan.Carefully stand peppers in pan and cover with aluminum foil. Bake 15 minutes in 400 degree oven; then uncover and bake about 5 to 8 minutes until a firm crust is formed on the tops.

Before serving, sprinkle remaining grated cheese over tops and place under broiler for 2 minutes. Serve hot.

TAGLIARINI VERDI AI QUATTRO FORMAGGI

(Green Tagliarini with Four Cheeses)

(6 to 8 servings)

I first tasted this dish at a dinner party in a typical Tuscan farmhouse outside of Lucca. To this day I do not know its true origins. 1/2 pound butter 1/4 teaspoon white pepper Pinch nutmeg 1/4 pound fontina or fonduta cheese, cubed 1/4 pound gorgonzola cheese, crumbled 1/4 pound Bel Paese cheese, cubed 1 cup grated parmesan cheese 1 cup heavy cream Approximately 1/2 pounds homemade tagliarini or dried green tagliarini

Melt butter in deep saucepan and season with pepper and nutmeg. Add fontina, gorgonzola and Bel Paese cheeses, and stir well until all have melted. Then blend in 1/2 cup parmesan cheese and all of the cream. Cook 5 minutes, stirring continually with a wire whisk. Bring to boil. Set aside, keep warm.

Bring 1 gallon of salted water toboil, cook homemade tagliarini 1 1/2 minutes; cook dried tagliarini 5 minutes. Drain well. Toss well with the sauce, and serve with remaining parmesan cheese and freshly ground pepper.

SCALOPPINE ALLA FRANCESE

Scaloppine French Style

(6 servings) 3 eggs Salt and white pepper to taste 1 tablespoon heavy cream 1 tablespoon parmesan cheese 1/2 tablespoon chopped parsley 12 veal scaloppine 1/2 cup flour 1/2 cup vegetable oil 8 tablespoons butter 1/4 cup dry white wine 2 lemons (juice of 1 1/2 lemons, and 1/2 lemon cut into 6 thin slices) 1/3 cup chicken consomme Pinch nutmeg

In large mixing bowl, make a smooth batter of the eggs, salt, pepper, cream, cheese and a sprinkle of parsley. Dust each veal scaloppine lightly with flour and soak slices in batter for 1 hour. In a large frying pan, heat oil until very hot. Carefully place scaloppine, 2 or 3 at a time, in pan, and cook quickly until they become crusty and of a golden color. Transfer to a warm platter. Set aside.

Melt the butter in a large baking dish, and arrange the veal scaloppine over the butter. Season with salt and pepper. Add remaining parsley and bake in preheated 350-degree oven for 5 minutes. Turn scaloppine, add wine and bake 5 more minutes. Add lemon juice and bake 3 minutes. Add consomme if scaloppine become too dry. Turn again and spoon sauce over all. Place in serving place in serving platter. Sprinkle nutmeg over it. Serve with slices of lemon.

ZABAGLIONE FREDDO

(Cold Zabaglione)

(6 servings) 1 pint fresh strawberries or blueberries 1 1/2 cups heavy cream 2 1/2 tablespoons sugar 8 egg yolks 2/3 cup wine, cognac or Grand Marnier 18 ladyfingers (optinal)

Clean berries under cold water. Hull the strawberries or remove the blueberry stems. Drain well and divide among 6 large, stemmed wineglasses. Refrigerate, whip the cream and when it is nearly thcikened add 1/2 tablespoon sugar, and continue whipping. Refrigerate. Put the egg yolks, remaining sugar, and wine, cognac or Grand Marnier into a round-bottomed copper pot, or round-bottomed glass bowl and sprinkle with a litte cold water. Place over boiling water, and beat the mixture rapidly witha wire whisk until it turns into a thick, creamy custard. Place pot over ice, and let cool before thoroughly blending in the whipped cream. Refrigerate for 1/2 hour. Pour over the berries. If you are using lady-fingers, arrange 2 or 3 in each glass. CAPTION: Picture, Alfredo Viazzi by Fred Sweets-The Washington Post; Illustration, no caption