IT'S SORT OF like the French version of peanut butter and jelly. There are no recipes for it -- you just smear a piece of chewy bread with fromage blanc and sprinkle it with fresh chives and diced, cooked ham.

It was one of the fast foods served at what amounted to a French homes show in Strasbourg last month. Among the fake fur-covered chaises, among the slice-and-dice-mounds-of-cole-slaw-machine demonstrations and the patio furniture, a large hall enclosed booths that sold bits and tastes of French foods and wines.

The tartine Alsacienne au bibeleskais follows the pattern for tartines, which require spreading something onto bread, but it veers from the traditional by calling for a fromage blanc (or bibeleskais) topping instead of jam.

Fromage blanc is a bland, very creamy young cheese that Rene'e Norman, a native of Alsace employed at the French Tourist Office, compares to cottage cheese, "only it's creamier." She says it's made with whole milk that includes the cream and is therefore much richer than cottage cheese and much smoother.

Like cottage cheese, fromage blanc is bland and the Alsatians dress it up, according to Norman, often with caraway seeds, sometimes with salt and pepper, and use it as a spread. To reproduce it in this country, Norman says she combines cream with cottage cheese. The cheese also resembles petit suisse, which is, on occasion, available at various specialty cheese stores in the Washington area. It's fresh tasting like sour cream, but thicker and richer.

There appears to be no formal heritage of this tartine Alsacienne. Diane Creedon of Food and Wines from France guesses that it might be a new invention, as the Alsatians are "always doing things with breads." Julia Child thinks that the recipe may be just too simple to have ever been recorded.

Simple and delicious it is. The bread slices come from a large, round, chewy loaf that makes the open-faced sandwich -- topped with this young cheese -- somewhat of a challenge to eat. You can substitute other young cheese for the fromage blanc or petit suisse -- softened cream cheese should be thinned with cream or milk, farmers' cheese could stand enrichment from cream or sour cream and cottage cheese should be blended. The fresh chives are chopped (substitute caraway seeds, finely chopped green chilies or green peppers). The diced cured ham can be saute'ed if desired and diced pepperoni or chorizo could easily take its place.

The sandwich is fast food with a touch of elegance and undeniable caloric extravagance. Serve it for dinner with a light zucchini soup, or use the topping on party rye or cucumber rounds and serve it as hors d'oeuvres.

The absolute authentic ingredients to reproduce this may take some real trouble to find. But in Alsace they created a quick dish from ingredients already at hand, and a reasonable facsimile could be reproduced in American kitchens keeping easy preparation as a priority. Dinner can be put together with one quick trip through the express lane of a supermarket, although it's assumed that every kitchen is equipped with flour, sugar, salt, pepper and butter or oil.

EXPRESS LANE LIST: Firm, fresh, chewy bread; sour cream or petit suisse; fresh chives (or the green ends of scallions, or caraway seeds); thinly sliced, good quality ham, such as Smithfield style or westphalian (or substitute hard sausage or bacon bits); zucchini; garlic; basil; chicken broth. TARTINE ALSACIENNE (4 servings) 2 to 3 ounces good quality, thinly sliced ham, diced Cooking oil, optional 4 to 8 large slices chewy bread (white, whole-wheat or seedless rye) 6 to 8 ounces sour cream, petit suisse or softened cream cheese 3 to 4 tablespoons chopped fresh chives, minced scallion tops, or caraway seeds

If you prefer a crispy ham topping, cook the diced ham quickly in hot oil and drain on a paper towel. Set aside. Top sliced bread with an ounce or so (to cover it liberally) of sour cream or petit suisse and sprinkle this with chopped chives and diced ham. ZUCCHINI SOUP (4 servings) 3 tablespoons vegetable or olive oil 2 to 3 cloves garlic, minced 2 to 3 zucchini, julienned or grated 1 teaspoon basil 5 to 6 cups chicken broth

Heat the oil in a saucepan. Add minced garlic. Stir 2 minutes. Add zucchini and stir quickly over high heat about 2 minutes. Add basil and chicken broth and simmer 10 minutes. Serve in heated bowls.