"There are 100 ways to make shish kebab," said Louis Assaff of East Detroit, Mich., who is Lebanese, "but I will tell you the best one."

The first requirement, he says, is high-quality, lean lamb. The next, a good fruity olive oil for the marinade. He prefers Sasso brand, from Italy. gAssaff gets the best results when he uses flat, stainless-steel skewers, which make it easier to cook the meat and vegetables evenly on each side. A common mistake, Assaff says, is to thread meat and vegetables onto the same skewer. They must be skewered and cooked separately, or else the mushrooms will burn before the lamb is even cooked rare, he says.

Assaff encourages cooks to add more garlic and other spices such as mint and soy soyce to the marinade if they want to. "And you needn't use all the vegetables in this recipe. Go to the market," he advises, " and buy what's fresh and looks good." LOUIS' LAMB SHISH KEBAB (6 servings) 1 cup olive oil 2/3 cup fresh lemon juice 1 clove garlic (or more to taste), crushed Dash salt 3 cherry tomatoes 6 small onions 6 large mushroom caps 2 zucchini, cut into 1 1/2-inch-thick rounds 1 small eggplant, cut into 1 1/2-inch cubes 1 green pepper, cut into 1 1/2-inch pieces 2 pounds lamb shoulder or leg, cut into 1 1/2-inch cubes Rice Pita bread

Stir together olive oil, lemon juice, garlic and salt. Dip vegetables into marinade; remove and set aside. Place lamb in marinade; let stand 20 minutes or more. Preheat broiler.

Thread vegetables on skewers, grouping together those that have the same cooking times. Onions will cook in 20 minutes; green peppers and eggplant, 15; zucchini, 10; mushrooms and tomatoes, 5. Divide lamb into 6 parts and thread onto 6 skewers.

Pour a little water into bottom of broiler pan and place skewers of lamb across pan. Place lamb 3 to 4 inches from heat and broil to taste, 15 to 20 minutes for medium, turning once or twice. Arrange vegetables skewers similarly over aluminum broiling pans into which a little water has been poured and place in broiler so that meat and vegetables are all done at same time.

Remove cooked vegetables from skewers and arrange on heated serving platter. Serve each person a skewer of lamb on a bed of rice and let guests help themselves to vegetables and pita bread. COLORFUL LAMB KEBABS (4 servings) 1 pound boneless lamb cubes 3/4 cup red wine vinegar 1/2 cup vegetable oil 1/4 cup sugar 1/4 cup water 1 tablespoon Worcestershire sauce 1 1/2 teaspoons celery salt 1 teaspoon salt 1 clove garlic, minced 1 bay leaf 2 carrots, cooked and cut crosswise into 1 1/2-inch slices 1 large cucumber, scored and cut crosswise into 1-inch slices

Place lamb cubes in bowl. Stir together vinegar, oil, sugar, water, Worcestershire sauce, celery salt, salt, garlic and bay leaf. Pour mixture over lamb cubes. Cover and marinate in refrigerator six hours or overnight. Add carrots and cucumber slices two hours or less before end of marinating time. Alternately thread lamb cubes, carrot and cucumber slices on metal skewers. Place kebabs across a broiler pan with a bit of water in it. Cook 15 to 20 minutes, turning and brushing with marinade occasionally.

This recipe uses the most inexpensive type of lamb chop.