Buckwheat is to food what solar is to energy.

The buckwheat seed, a fruit actually and not a grain, contains more high-quality protein than any other food in the plant kingdom, according to a Department of Agriculture study. It's clean, requiring no herbicide or pesticide for growing. It's hearty, thriving in cold weather and returning nitrogen to the poorest soil.

So why doesn't everybody eat buckwheat? After Middle Europeans immigrated to America, buckwheat consumption went up, but fell off as they "got caught up in the food trends of this country," says John McMath, an environmentalist and farmer who spreads the word about buckwheat the way Johnny did appleseeds. Consumption has been low until 10 or 12 years ago, when people became interested in nutrition, he adds, and the trend back to buckwheat has begun.

A spokesman for the National Buckwheat Institute, McMath says that the popularity of buckwheat is growing, especially among the elderly, because it is nutritious, cheap and easy to prepare. Runners, those prototypes for the health-conscious generation, are eating buckwheat because it provides a pleasant change in a diet that relies heavily on complex carbohydrates.

The major supermarket chains in the Washington, D.C. area carry buckwheat groats, although the product is sometimes a little hard to spot. Look for it in the "gourmet" section or shelf with imported or fancy food, near "health" or kosher foods.

The following meal should be no problem to prepare, as long as you have flour, sugar, salt, pepper and butter and/or oil in the kitchen at home.

EXPRESS LANE LIST: kasha (toasted buckwheat groats), eggs, spinach, almonds, horseradish, sour cream, chicken, tarragon. KASHA PILAF (6 servings) 1 cup toasted buckwheat groats (kasha) 1 egg, beaten 1/2 teaspoon salt 1/2 teaspoon freshly ground pepper 2 tablespoons butter

1/2 cup slivered almonds

Bring 2 or more cups of water to a boil. In the meantime, combine kasha, egg, salt and pepper in a 2-quart saucepan. Stir over medium heat until egg is set and buckwheat kernels are separate and dry. Add 2 cups boiling water (or bouillon) to kasha, cover pan and cook over low heat until kasha is tender, about 15 or 20 minutes. Meanwhile, melt butter in large skillet over medium heat. Add almonds and stir over heat until they are lightly toasted. Remove from heat. Add to kasha before serving. CREAMED SPINACH (6 servings) 2 10-ounce bags fresh spinach or 2 10-ounce packages frozen, chopped spinach 1/2 to 1 cup sour cream 1 to 2 tablespoons prepared horseradish

Clean, trim and chop the spinach and cook in a dry, covered saucepan over medium heat until the spinach is wilted. (If using frozen, chopped spinach cook to thaw and evaporate all water, then proceed.) Stir in sour cream and horseradish. Serve hot. CHICKEN RUSSE (6 servings) 1 teaspoon tarragon 3 to 4 tablespoons butter, softened 6 to 8 serving pieces of chicken Dry wine, optional

Combine tarragon and butter; spread on chicken. Place them, skin side down on a rack in a shallow pan. Place pan about 6 inches from the broiling element and broil about 10 minutes on each side, basting chicken with pan drippings, and wine, if desired. Allow a little more time for dark meat.