When it gets to be about 5 p.m., the collective stomachs and collective brains of single cooks start to rumble all over town . . . what's to eat for dinner? Will it be Mrs. Paul's or Mr. Henry's? Frozen waffles or fancy carryout?

Whatever the answer, many single cooks head for the store. Impromptu, one-night-stand shoppers, single cooks often end up spending a lot of little chunks of time in the supermarket, grabbing for the craving of the evening or flipping through the Lean Cuisines to find the one that boils in 12 minutes.

For some single cooks, the idea of stocking up once a week with a load of groceries is for families and hungry teen-agers. They would rather face rush hour in the express lane every rr other night then plan ahead.

While it is true that single cooks are somewhat limited in the possible variations in meal plans -- they risk facing rotting leftovers and half-empty tomato paste cans should their menus get too diversified -- it's certainly not impossible to have a varied dinner regimen.

Because many single cooks prefer simple dishes when it comes to cooking for one, buying one or two main dish ingredients that can be mixed and matched in four or five dinners is all the planning ahead that single-cook style requires.

Cubed eggplant, for example, can be skewered with other vegetables in a veggie shish kebab and served over rice or couscous one night, with the remaining eggplant half stuffed with the leftover grain, chopped scallions, plum tomatoes and some zippy spices for the next. A packet of four chicken breasts can be given multiple treatments: one portion saute'ed lightly in butter, lemon juice and fresh mint one night, and another marinated overnight in ginger, sesame oil and soy sauce for the next. The remaining two can be frozen or made into curried chicken salad for a meal later in the week.

The following meal plan includes a shopping list of 18 ingredients that can be stretched into five simple-to-prepare dishes -- with little or no leftovers. You will also need to have some ingredients already on hand, such as spices and oil.

The first dish should be made on Sunday, since it requires about two hours to cook, but everything else can be cooked in 30 minutes or less. Be flexible with the menu; if you feel like eating the burgers on the second night instead of the third, go ahead. And feel free to omit the bacon or egg. A Plan-Ahead Week of Meals

Day 1: Cincinnati Chili

Day 2: Spinach Salad with Wild Mushrooms and Homemade Blue Cheese Dressing

Day 3: Vermicelli with Cold Tomato Sauce and Italian Bread Brushed with Garlic Butter

Day 4: Herbed Blue Cheese Burger with Oven-Baked Lemon-Pepper French Fries

Day 5: Green Pea Soup with Grilled Zucchini-Cheddar Sandwich

Have on Hand Bay leaves, garlic, cinnamon, allspice, vinegar, crushed red pepper, chili powder, cumin, oregano, basil, thyme, oil (olive and vegetable), butter, egg (optional), worcestershire sauce, chicken broth, sesame seeds (optional), salt, pepper, sugar.

Shopping List 1 2/3 pounds lean ground beef (approximately), 6-ounce can tomato paste, 2 large red onions, 15-ounce can dark red kidney beans, vermicelli, 4-ounce package grated cheddar cheese, 2 ounces wild mushrooms, 1 bunch parsley, uncut loaf of italian bread, 1/3 pound fresh spinach, 1 small green pepper, bacon (optional), 2 plum tomatoes, small wedge blue cheese, plain lowfat yogurt, 1 potato, 1 lemon, 10-ounce package frozen green peas. Fruit Dessert Possibilities

The meal plan does not include desserts, but if you like something more elaborate than a plain piece of fruit, here are some quick two- and three-ingredient ideas that you can add to your shopping list:

*Slice a pear into wedges and place in a small baking dish. Drizzle lightly with maple syrup and a few drops of vanilla and bake at 350 degrees for 10 to 15 minutes.

*Before you leave for work, peel an orange and cut it into crosswise slices. Place in a shallow dish and cover with liqueur such as Cointreau or brandy. To serve, drain and serve orange slices over vanilla ice cream, if desired.

*Thaw a package of frozen raspberries in hot water while you eat dinner. Then pour the juice and some of the berries over a scoop of ricotta cheese. Stir the rest of the raspberries into plain yogurt for breakfast the next morning.

When You Get Home 1) Separate about six ounces of the meat from the ground beef. Shape into a patty and freeze (if you plan to eat it later in the week) or refrigerate (if you plan to eat it sooner).

2) Have small containers, foil or plastic bags at hand. You will use them for the leftover tomato paste, cheddar cheese and zucchini, and to freeze the remaining chili. What to Do With Leftovers

Italian bread: Make french toast by soaking thickly sliced bread in beaten eggs, milk, a drop of vanilla and a few shakes of allspice.

Blue cheese: Crumble into an omelet for brunch. Add a few wild mushrooms, if you have some left.

Blue cheese dressing: Use as a dip for fresh veggies or to coat chicken breasts.

Parsley: Make a parsley butter sauce for leftover vermicelli. Add a couple of fresh mussels or clams. CINCINNATI CHILI (4 servings)

Salt for saute'ing meat

1 1/4 pounds lean ground beef

3 bay leaves

1/2 cup chopped red onion

1 small onion, chopped

3 medium cloves garlic, finely chopped

3/4 teaspoon cinnamon

1 1/2 teaspoons allspice

2 tablespoons vinegar

1/2 teaspoon crushed red pepper

2 tablespoons chili powder

1 teaspoon cumin

1/4 teaspoon oregano

1 teaspoon sugar

1/2 6-ounce can tomato paste

3 cups water

15-ounce can kidney beans, drained

FOR SERVING: (1 serving)

1/4 pound vermicelli, cooked

2 tablespoons cheddar cheese

1 tablespoon grated onion

Sprinkle a sparse layer of salt in a heavy skillet. Place skillet over medium heat and add ground beef when skillet is hot. Cook until brown. Stir in remaining ingredients except kidney beans, vermicelli, cheese and grated onion. Bring mixture to a boil and simmer, uncovered, for about 1 hour and 45 minutes, skimming fat from surface as necessary. Add kidney beans about 30 minutes before the chili is done. Taste and adjust seasonings before serving.

To serve, place small amount of cooked vermicelli in a deep soup bowl. Spoon over chili. Top with grated cheese and raw onion. Freeze remaining chili. SPINACH SALAD WITH WILD MUSHROOMS AND HOMEMADE BLUE CHEESE DRESSING (1 serving)

* 1/3 pound fresh spinach

2 tablespoons chopped red onion

1 egg, hard cooked

1/2 small green pepper, sliced

1 ounce wild mushrooms, such as enoki or shiitake

1 plum tomato, quartered

2 strips bacon, cooked and crumbled

1 tablespoon toasted sesame seeds (optional)

FOR THE DRESSING:

1/2 cup lowfat yogurt

5 tablespoons blue cheese, crumbled

2 teaspoons lemon juice

1 teaspoon chopped red onion

1/4 teaspoon worcestershire sauce

Freshly ground pepper and salt to taste

ld,10 Assemble salad ingredients. Process dressing ingredients in a food processor or blender until smooth, and pour over salad. VERMICELLI WITH COLD TOMATO SAUCE (1 generous serving)

* 1/2 zucchini, sliced

Olive oil for sauteing, plus 1 tablespoon for sauce

1 ounce wild mushrooms

Scant 1/4 pound vermicelli

1/2 6-ounce can tomato paste

1 clove garlic, crushed

1/8 teaspoon crushed red pepper or to taste

1/4 cup minced parsley

FOR THE GARLIC BREAD:

2 teaspoons butter

2 slices italian bread

1 large clove garlic, minced

Saute' zucchini in a small amount of olive oil about 5 minutes. Add mushrooms and saute' lightly for another 3 minutes. Cook vermicelli until al dente.

Mix 1 tablespoon olive oil with tomato paste, garlic, red pepper and parsley. Stir into vermicelli. Toss zucchini and mushrooms with vermicelli and serve.

To make garlic butter bread, melt butter in a small saucepan and add garlic. Cook for 2 minutes. Brush onto bread slices and broil for 3 minutes, or until bread is lightly toasted. HERBED BLUE CHEESE BURGERS (1 serving)

* 6-ounces lean ground beef

3/4 teaspoon minced fresh parsley

1/8 teaspoon dried oregano

1/4 teaspoon dried basil

1/8 teaspoon chili powder

1/4 teaspoon freshly ground black pepper

1 heaping tablespoon crumbled blue cheese

Italian bread for serving

Mix ground beef with all ingredients except blue cheese. Shape into two patties. Place blue cheese on top of one patty and cover with remaining patty. Seal in cheese by pinching edges of meat together.

Broil for 5 minutes on each side. Serve on italian bread, alongside lemon-pepper french fries. OVEN-BAKED LEMON-PEPPER FRENCH FRIES (1 serving)

1 teaspoon olive oil

4 teaspoons lemon juice

1 potato, peeled and cut into 1/2-inch wide strips

Freshly grated black pepper

Mix olive oil and lemon juice together in a bowl. Add sliced potatoes and toss until potatoes are coated. Spread potatoes on a greased cookie sheet or aluminum baking dish.

Bake at 475 for 30 minutes. Turn strips periodically during cooking to brown all sides. (Run under broiler for 2 minutes for crisper fries). Grate a generous amount of fresh black pepper over fries, a squeeze of lemon juice, if desired, and serve. GREEN PEA SOUP (2 generous servings)

2 slices bacon, cut in small pieces, or 2 teaspoons oil

1/2 cup red onion, chopped

10-ounce package frozen green peas

1 cup water

1/4 teaspoon thyme

1/4 teaspoon freshly ground black pepper and salt to taste

2 cups chicken broth

1/3 cup yogurt

In a large saucpean, cook the bacon over low heat until golden brown. With a slotted spoon, remove all but a few pieces of bacon and drain them on paper towels. Pour off all but a thin film of fat from the pan. Add onion and cook until soft, but not brown. (If you do not eat bacon, just saute' the onion in 2 teaspoons oil.)

Add peas, water, thyme and pepper, and cook until peas are just tender. Cool slightly and pure'e, 1 cup at a time, in a food processor or blender. Pour back in saucepan and stir in broth. Bring to a boil, then lower heat and simmer 15 minutes.

Put yogurt in a bowl; add 3 or 4 tablespoons of hot soup, stirring to make a smooth mixture. Stir this into soup, taste and add salt if needed. Heat gently, not letting it boil, and serve hot, with a sprinkling of bacon. agcrdt3 Adapted from "Beautiful Soup," by Dorothy Ivens (Irena Chalmers Cookbooks Inc., $2.75) BROILED ZUCCHINI-CHEDDAR SANDWICH (1 serving)

2 teaspoons olive oil

2 tablespoons finely chopped red onion

1 clove garlic, minced

1/2 small green pepper, thinly sliced

1/8 teaspoon each basil and oregano

1/2 cup zucchini, sliced thinly

Italian bread for serving

1 plum tomato, sliced

1/4 cup grated cheddar

1/2 teaspoon minced parsley

Heat olive oil in a skillet. Add onion, garlic, green pepper, basil and oregano, and saute' until onion is translucent, about 5 minutes. Add zucchini and cook over low heat until tender-crunchy, about 10 minutes. Layer zucchini mixture open-faced on a sub-sized section of italian bread. Top with tomato and grated cheddar and broil until cheese is melted. Sprinkle with minced parsley.