Instructions: Before Columbus, gazpacho was pristine white. Almonds, pounded in a mortar with chilled well water, rustic bread, garlic and olive oil, created creamy, thick ajo blanco. Garnished with green grapes, the cool, pale soup was soothing sustenance in an arid land. It was only after the arrival of the tomato from the New World centuries later that gazpacho blushed red.

Gazpacho is one of the oldest dishes of Spanish cuisine, and one of the best known. To understand the gazpacho found today on almost every restaurants summer menu, you must understand its ancient, rural origins.

While on vacation in Spain last spring I met Clara Maria G. de Amezua, a scholar, author and teacher of Spanish cuisine. Although the letter G. in her name stands for a family name, in truth, I think it must stand for gazpacho, for she is one of the countrys leading experts on its history. These are some of the things she told me.

In heat-blistered and sun-parched Andalusia, the southernmost province in Spain, food has always had to be light, easily digestible and wilt-resistant. It needed to be cool, refreshing and thirst-quenching as well, and had to contain enough salt to replace losses through perspiration. To meet all of these requirements, Spanish cooks created gazpacho.

As early as the 17 th century, properly made gazpacho was so nutritious and important in Spain that for many it was almost the sole source of nourishment.

It was King Philip IVs law that "two pounds of bread and olive oil for the gazpacho" be given to field workers each day. Farmhouse managers designated a special person called a gazpachero to prepare the dish for the field workers main meal. In the winter, the mixture was warmed into a nourishing stew. This was survival food.

Stale bread was ever-present in the diet of rural people. In villages, where a familys bread was baked only once a week, housewives would make up their dough, marking each unbaked loaf of bread with a personal stamp for identification. The bread was then carried in baskets to a community oven to be baked.

The challenge was how to utilize every precious bread crumb. So with mortar and pestle, cooks ground stale bread, almonds and garlic to a paste, adding olive oil and salt, and thinning the mixture with water. Sometimes pine nuts or cooked lima beans were substituted for the almonds. These earliest white gazpachos were left to sit in the cool shadows until mealtime. Served with a glass of crisp white wine, gazpacho made a complete meal.

Olive oil was essential to gazpacho for its nutrition and staying power as well as its flavor and fragrance. Spaniards, surrounded by the olive trees that gave them their livelihood as one of the worlds biggest producers and exporters of olive oil, were eating the purest of todays much-heralded Mediterranean

Green gazpachos were made by mashing herbs such as cilantro and basil into the mixture and then topping the mixture with chopped lettuce. The green soups are almost forgotten today.

Enter the first tomato. Seville, which served as the entry point for the new food products that explorers and colonists brought back from America, saw the first tomatoes and peppers from the New World. These new ingredients transformed the traditional dish.

There are as many versions of modern gazpacho as there are cooks. Some like the soup thick and chunky with vegetables; others puree it and pass chopped vegetables at the table. Some prefer an intense garlic flavor, while others prefer a more subtle flavor. Chilies can give gazpacho a kick. Bread, stale or otherwise, isnt usually used, nor are nuts. About the only agreement today is that gazpacho should contain tomatoes and be served cold. The mortar and pestle are long gone, replaced by the electric blender.

Gazpacho is a summer salad posing as a soup. It can be composed of whatever is ripe in the garden. Luscious, vine-ripened tomatoes usually form the base. A clove of garlic, an onion, red or green peppers and cucumbers are the supporting cast. Olive oil, wine vinegar, salt and pepper dress the salad. Chopped egg, fried bread cubes, diced onion, tomato, cucumber and bell pepper are garnishes.

In the American Southwest, around Santa Fe, New Mexico, cooks add lime juice, fresh herbs and hot chilies. They serve the soup in hollowed-out, extra-large beefsteak tomatoes, placed on shaved ice and garnished with minced jalapenos, green onions and chopped avocado.

Its hard to think of a dish that better fits the bill of the traditional heart-healthy Mediterranean diet, rich in non-processed and simple foods such as vegetables, grains and nuts and, its mainstay, olive oil.

Marlene Parrish is a cookbook author and food writer based in Pittsburgh.

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