Writers of cookbooks may well wonder if there is an audience out there. With the soaring sales of convenience foods and the dramatic increase in eating away from home, is anyone out there cooking?

Frances M.H. Grundy is. Not only does she cook, she reads cookbooks as well and enjoys doing both. Her work-she is that rare and prized convenience, a genuine English baby nurse-allows time for these avocations and acess to private libraries. Frugal but open-minded, she saves leftover vegetables and their cooking water to make soups, but will experiment with an exotic recipe from the Balkans. She bakes bread regularly and makes her own Damson plum gin. In sum, she is the sort of person serious food writers talk at with their typewritters.

Not that the cookbook collection in her tidy Connecticut Avenue apartment is large. (There are several dozen volumes, as well as a collection of Gourmet magazines and files and folders of clipped in the kithcen.) It's she uses the books. "I read them for pleasure," she said one morning last week. "They give me a great deal of joy. I look for ideas as well as recipes but I like the chatty ones best."

A recipe, she feels, can be a taking off point for improvisation. Chicken plus onions and potatoes and whatever vegetables are at hand can be blended into a soup. As a variation on broccoli, she will cook the stems with onion, make them into a puree and serve it with the steamed, still crisp florettes atop.

She pulls out a recent edition of Mrs. Beeton's famous Victorian guide for homemakers, and frowns. "Now this won't do. It has pressure cooking in it. They've stuck that in." More to her liking are two others: "Food in England" by Dorothy Hartley (1954) and a worn copy of "In Defense of British Cookery, 200 Wonderful Recipies That Prove the English Can Cook" by Audrey Alley Gorton (1960).

These titles testify to Miss Grundy's Englishness, but she has practised cookery in her homeland only rarely. Her career led her to central Europe and France before World War II and then to this country. She has been a resident of this city for the past four years, but frequency is called back for duty to Cleveland where she lived last.

The life style of clients in that city has played an important part in the growth of her cooking repertoire. "It's not like New York or Connecticut," she said. "With all the servants and cooks, I would go into the kitchen but only stick my finger in if somebody was doing something horrible. In Cleveland they have huge houses, but not a lot of help. They prefer to do things themselves. The people found out I liked to cook. Sometimes I'd wave it under their noses because the mothers were just back from the hospital and it made the daddies like me. I'm not a very fancy cook, but they would say they were glad to have me because they were in such a rut about eating."

So she would cook the father Oriental flank steak, beefsteak and kidney pie, duck a la orange or stuffed chicken breasts. At mid-day she connected salads for the mother, all the time tending to the new baby. Mary Poppins with her umbrella was never more welcome than Frances Grundy with a bag of groceries. Often, when she left, her employers would present her with one of the cookbooks she had been reading in spare moments.

Among them are regional recipe books from Cleveland, Cincinnati and Hewlett, N.Y.; James Beard's "American Cookery"; "The American Heart Association Cook-book," and the Penguin collection of Elizabeth David's works ("those are fantastic"). Her newest acquisition is a book on veal cookery.

Not only is Frances Grundy a reader of cookbooks, she is a cookbook contributor. A favorite recipe was included in "Bach For More," compiled by the Junior Committee of the Cleveland Orchester. But the title the editors gave it offended her. They called it "Super Subs." "Can you imagine a nice English lady making that?" she complained. "Mine are 'ham rounds.'"

The original recipe follows:


(Makes 20 to 24) 3 1/2 cups chopped lean cooked ham 6 ounces cream cheese, at room temperature 4 tablespoons margarine, at room tempeture 1 tablespoon Dijon-style mustard 2 teaspoon finely grated union 2 teaspoon horseradish 1/2 teaspoon Worcestershire sauce 1 rounded tablespoon capers 6 tiny sweet pickles (gherkins), coarsely chopped 2 tablespoon chopped fresh parsley Fresh nutmeg to taste 1 loaf French bread

Combine ham, cream cheese, margarine and mustard. Then add onion, horseradish. Worcestershire, capers, pickles, parsley and nutmeg. Mix well.

Cut French bread in half crosswise and scoop out soft center of each half without scrapping the sides or breaking through the end. Stuff the hollows with the ham mixture, pressing it down to the ends. Cover the exposed ends with foil and place in the freezer for at least 2 hours. (The recipe may be prepared a day ahead: if so, wrap both pieces completely in foil or freezer paper.)

Preheat oven to 42 degrees. Heat the two halves for 10 minutes. The centers should still be cold. Slice each half into 10 to 12 rounds, using a serrated knife. Serve while still warm. CAPTION: Illustration, No caption, Illustration by Terry Dale for The Washington Post; Picture 1, Frances M.H. Grundy collects cookbooks. By James A. Parcell-The Washington Post; Picture 2, Grundy: "I read them for pleasure." By James A. Parcell-The Washington Post