American fast food favorites such as Big Boy hamburgers, slurpees and 21 flavors of ice cream reign supreme on the ground floor of an old colonial hotel in the commercial heart of New Delhi -- normally the home of curry, samosas and tandoori chicken.

It is an unabashedly imitative operation, right down to the merchandise techniques and the design on the cups that the ice cream is served in.

There is,for example, a "Hot Shoppe" that differs very little from the Washington-based chain. Even the logo is similar, although the two U.S.-trained brothers who run the operation insist it was designed in Delhi.

Next to the Hot Shoppe is Nirula's 21 Ice Cream Parlor. It looks exactly like a Baskin-Robbins, has a logo with 21 in a circle for the number of flavors, and serves ice cream in cups with colored dots on them.

"It's direct plagiarism," said Deepak Nirula, one of two young brothers who both graduated from the Cornell University School of Hotel Management and who run the Hot Shoppe, the ice cream parlor, the hotel and other fast food establishments at the corner.

It is hard to tell whether he is joking or not.

Deepak and his older brother, Lalit Nirula, have registered their names as trademarks in India. When Washington's Hot Shoppes heard the Nirulas were using a similarname, "they told us to stop immediately and to burn all material with the name on it," Deepak Nirula said.

"We told them if they tried to come to India, they would have to pay us for the use of the name."

THE NIRULAS' operation here is an example of the borrowing of design and merchandising ideas that occurs with increasing frequency throughout the world.

At its worst, it involves the piracy of a well-known trademark product. Cartier, the French-based jewlers, have spent hundreds of thousands of dollars to force a company using the same name to stop doing business in Mexico City. Carter finally decided to open its own shop there and compete directly.

Similarly, bazaars around the world carry watches, radios and other electronic goods whose names are one letter away from their famous counterparts, but whose quality is vastly inferior.

The Nirulas' enterprises do not fall into that category. The quality is high and thier shops would not be an embarrasement to either Hot Shopes or Baskin-Robbins.

While they have copied rames, ideas and merchandising techniques, the Nirulas have added a distinctly Indian flavor to their operation.

The Hot Shoppe, for instance, sells masala dosas, spicy stuffed rice flour crepes that are a south Indian delicacy, along with hot dogs and hamburgers. For fast food convenience, though, the Nirulas omitted thesambar, a peppery vegetable sauce that goes over the masaladosa. Purists might complain, but they are selling like hot cakes.

Similarly, the hamburgers are made of chopped mutton, which often as not here means goat meat. Beef is taboo for Hindus, who make up the bulk of India's population. Buffalo, which is eaten by many here as a substitute for beef, is considered suspect by too many people to be served in a mass-feeding operation.

WHILE VANILLA is the best-selling ice cream flavor here as in the United States, the numbertwo favorite is called "gulabo" and contains real rose petals. These are followed in popularity by strawberry and a purely Indian delight called "badaam kewra," an almond-jasminecombination.

"They would go well in California," said Deepak Nirula.

Some of the ice cream flavors such as jamocaalmond fudge, rum raisin, goody-goody gumdrops and toasted almond are familiar to any Baskin-Robbins aficionado.

Butothers are Nirula concoctions such as "21 love" (vanilla with small chunks of chocolate), "wild Willie walnut" and "mango tango," with pieces of fresh mango.

"We use wilder names than Baskin-Robbins," said Deepak Nirula. Among them are"Casablanca" (a fig ice cream with toasted melon seeds) and"ginger rogers" (ginger ice cream). But even with the imaginative names, those flavors, along with cardamon seed ice cream, never really sold well.

Neither do sloppy joes or chili or breakfast. However, other American fast foods go down well. A Big Boy hamburger is a favorite as is Nirula's version of the Big Mac -- a "mahaburger." Hot dogs and pizzasalso sell well.

"The people obviously wanted something,"said Lalit Nirula.

He and his brother go to the United States at least once a year for new, improved fast food ideas. But, he said, "You can't copy exactly."

It's close enough, however, to fool any American walking down the street.