Atmosphere: Fast food with a touch of class.

Prices: Burgers and other international snacks from 80 cents; a full dinner can be put together from the stalls for about $3.

Hours: Monday through Saturday. Breakfast, 6:30 a.m. to 10:30 a.m.; a full dinner can be put together from the stalls for about $3.

Hours: Monday through Saturday. Breakfast, 6:30 a.m. to 10:30 a.m.; lunch, 11 a.m. to 3:30 p.m.; dinner, 5:30 to 11 p.m. The bar is open from 11 a.m. to 1 a.m.

Credit Cards: Cash only.

Reservations: None.

Special facilities: Free parkling; adjacent to Metro stop; boosters and high chairs available. Because of the many steps, accessible to handicapped through elevators in underground parking lot.

The consumers of 3 billion McDonald's hamburgers have borne witness to a dietary fact of life: Americans like their foot fast. And although taste can be a negotiable item, price is almost as important as speed.

The cafes that have sprung up in malls around the metropolitan area seem cognizant of their diners' prerequisites, but in addition, they have added something to the fast-food formula - interesting food. The most recent opening of the mall cafes, the Crystal Dinery in the Crystal City Underground, may be the granddaddy of them all. Not only are there menus from 11 different cuisines, all served instantly and cheaply, there is also an all-day bar - and atmosphere. Lots of it.

Approaching the Dinery from the parking lot, there is a gorgeous skylit staircase, lavishly decorated with greenery and glass. At the bottom of the stairs there is a secluded pub with wooden tables and chairs, nestled among more plants. Near the nook is a bar, done up in turn of the century decor as is most of the underground section of the mall.

In thecenter of the Dinery, surrounded by several stalls, is a raised platform with more tables.

On the night our family visited, the overhead rotating fans were festively hung with red, pink and green papier mache flowers in celebration of Mardi Gras - the Dinery's theme of the month. Along the brick walls were cleverly designed green taffeta palm trees with shocking pink leaves, and a band imported from New Orleans serenaded diners with Dixieland.

The music was the best break my husband and I have had recently in a restaurant. Our 3-year-old son was so entralled with the tuba player, we had more than enough time to choose what cuisine to sample: There is a problem here for the indecisive since there is the usual face of pizza, pastas, hamburgers and deli sandwiches, plus a Back to Nature menu with such intriguing titles as sky high vegetable bake and enchanted mushroom stew. French offerings of crepes and quiche, Chinese egg rolls or combination dinners, German sauerbraten, Mexican tostadas, Greek sandwiches and delicacies, hot and cold soups, salads of all sorts and at the end of the line a beautiful pastry counter with exotic coffees.

We decided to split the nationalities. My husband took Italian, Iasagna with garlic bread for $2.03, and I took French, a better buy with beef bourguignon, rice, peas, beans and bread and butter for $2.61.

For our small hot dog fan, it was a bratwurst and a soda for $1.61. Two iced teas cost 52 cents.

The food at the Dinery would certainly not satisfy gourmet standards, but it is after all not a gourmet place. The service was fast, the food reasonably well prepared - certainly a nice break from other fast-food restaurants - and for the money, we felt, a good buy.

And we enjoyed the music. The folks who surrounded us at nearby tables seemed equally enthusiastic about the entertainment. The man next to us couldn't have looked more at home as he sipped his whiskey sour while two strolling banjo players serenaded him with "When You're Smiling." His sons, munching ice cream cones, seemed equally comfortable as they relaxed while waiting for their mother to finish shopping in the mall.

Leo Kretikos, one of the Dinery owners, told us later that the Dinery will continue the evening entertainment from 5:30 to 11 each night although the type of music will change from time to time. For August, there will be a country-western show, to be replaced in September with groups from different nationalities playing each week.

The only disappointment of the meal was the desert - two eclairs, a napoleon and two cappucinos, which cost $4.43.The pastries were soggy and the filling pasty; the coffee, too sweet, but for a total bill of $11.20 we felt we could afford the disappointment.