* Single cooks are condiment connoisseurs. Ask them what they have in their refrigerators, and they'll give you a detailed explanation of the jellies, jams, mustards, parmesan cheese, relish, ketchup and olives that line the side shelves like wallflowers at a junior high school dance.

Ask them what's in there for dinner, and they'll say nothing.

It's time for single cooks to broaden the horizons of their refrigerator regulars. After all, jelly wasn't made just for toast or peanut butter and olives can do very well without martinis.

This philosophy will not only shave time for the single cook (home from work without a trip to the market, or maybe just a quick one), but it will divert those future mold-makers from their trip to the garbage pail. And if the single cook is lucky, of course, the proper combination of odds and ends will be used without creating the problem of new leftovers.

Spike ordinary dishes with additions not normally used. Don't forget about the pickle relish when making tuna and egg salad. Grate some leftover ginger over a baked pear or over fish and bake topped with paper-thin slices of lime or lemon. Sprinkle grated parmesan and a squeeze of lemon juice over the aging mushroom caps in the hydrator and broil for a few minutes until the cheese is melted.

And practically any jar -- including horseradish, hot pepper sauce and olives -- in the refrigerator will do well in potato salad, the greatest of condiment vacuums.

Combine condiments to make new sauces or dressings. Give yogurt or mayonnaise a hit of dijon-style mustard first before mixing it into tuna, turkey or egg salads. Liven up the commercial barbecue sauce that's been sitting on the shelves since August with garlic, ginger or hot pepper sauce. Make a chutney salad dressing by combining two tablespoons chutney with 1 1/2 tablespoons white wine vinegar with a quarter cup of oil. Season it with curry and cayenne and serve over fruit, chicken or ham.

Jean Anderson and Ruth Buchan, in their 1980 Tastemaker Award-winning book, "Half a Can of Tomato Paste & Other Culinary Dilemmas," offer some other ideas:

* Transform the leftover bread sitting in the refrigerator into bread crumb toppings for vegetables or casseroles. Add either leftover minced parsley, dried herbs or minced nuts to the bread crumbs. Mix bread crumbs with some melted butter and season with cinnamon, nutmeg or cloves for a topping for baked fruit.

* Use jellies and jams to glaze beets, turnips, rutabagas, winter squash or parsnips. Add a tablespoon or two to the finished drained, cooked vegetable along with an equal amount of butter and shake briskly over low heat until the vegetable glistens. Or add a tablespoon of jam or jelly in the hollow of an acorn squash with an equal amount of butter and bake for 45 minutes to an hour in a 375-degree oven.

Scramble minced green olives into eggs or mix into chili.

* Use leftover parsley for other purposes than cosmetic. Use it to improve almost any savory dish -- soups, sauces, sandwich spreads, vegetables and salad dressings.

* Make a quick tomato soup by combining 1 part leftover tomato pure'e with 1 1/2 parts each beef consomme' and milk. Heat, but do not boil. Season to taste with salt, freshly ground black pepper and marjoram, tarragon or rosemary with thyme. Stir one to two tablespoons leftover tomato paste into baked beans, creamy salad dressings, cheese spreads or burgers.

Here are some other recipes to hone single cooks into even sharper condiment connoisseurs: MUSTARD-PARMESAN CHICKEN (1 serving) 1 skinless, boneless chicken breast half 1 to 2 tablespoons coarse or dijon-style mustard 1 tablespoon bread crumbs, preferably whole wheat 1 tablespoon parmesan cheese 1/2 teaspoon dried dill, basil, tarragon or sage

Coat chicken breast half with mustard. Combine bread crumbs, parmesan cheese and herb and roll chicken breasts in breading.

Place on greased baking sheet and bake at 350 degrees for 20 minutes. CARROTS GLAZED WITH MARMALADE AND GINGER (1 serving) 2 carrots, thinly sliced 1 1/2 teaspoons butter 1 teaspoon grated fresh ginger 1 1/2 teaspoons lemon juice 2 teaspoons orange marmalade or other tart fruit jelly Salt and freshly ground black pepper to taste

Place the carrots in a small saucepan, barely cover with water and bring to a gentle simmer. Cover and cook for about 15 minutes, or until the carrots are tender.

In another saucepan, combine the butter, ginger, lemon juice and marmalade and heat, stirring, for 3 minutes over moderately high heat. Drain carrots and combine with glaze until well coated.

Season with salt and pepper and serve. Adapted from "Half a Can of Tomato Paste and Other Culinary Dilemmas" (Harper and Row, $9.95) PARSLEY AND OLIVE SALAD SANDWICH (1 serving) 3 tablespoons pimento-stuffed green olives, sliced 2 tablespoons chopped walnuts 1/3 cup parsley, finely chopped 2 teaspoons olive oil 1/2 teaspoon lemon juice 10 capers 1/2 clove garlic, minced Hot pepper sauce to taste

Baguette or sour dough roll for serving

Combine all ingredients and insert into baguette or sour dough roll. Adapted from "The Feast of the Olive," by Maggie Blyth Klein (Aris, $9.95) BROILED HAMBURGERS WITH ROQUEFORT-HORSERADISH TOPPING (Enough for 2 hamburgers) 1/4 teaspoon paprika 2 teaspoons finely minced onion or scallions 1 tablespoon prepared horseradish 2 tablespoons crumbled roquefort or blue cheese 2 teaspoons ketchup, tomato paste or chili sauce 2 4-ounce hamburger patties

Combine all ingredients except ground beef.

Broil hamburger, allowing fat to drip into broiler pan. When burger is almost done, top with roquefort-horseradish spread. Return to broiler and heat about 2 minutes, or until cheese is just melted. Adapted from "Half a Can of Tomato Paste and Other Culinary Dilemmas" (Harper and Row, $9.95) SWEET AND SOUR STIR-FRIED SHRIMP (1 serving) Oil for stir-frying 1 small clove garlic, minced 1/2 teaspoon minced fresh ginger Whatever vegetables are in the hydrator, such as: carrots, celery, scallions, broccoli or mushrooms, sliced 1/3 pound shrimp, cleaned and deveined 2 tablespoons chopped walnuts (optional) Rice for serving FOR THE SAUCE: 1 teaspoon soy sauce 1 tablespoon jelly 2 tablespoons ketchup 2 tablespoons vinegar 2 tablespoons water 1/2 teaspoon cornstarch

Coat a wok or skillet with oil. When hot, add garlic and ginger and stir-fry for 20 seconds.

Add vegetables, starting from the crunchiest and ending with the softest, stir-frying each for about 30 seconds. Add shrimp and continue stir-frying for another 30 seconds.

Add combined sauce ingredients and stir-fry for another 2 to 3 minutes or until shrimp turn white. Add optional nuts during last 30 seconds of cooking.

Serve with rice.