GLENDALE, Calif. (AP) _ Baskin-Robbins, the granddaddy of franchised ice cream, is launching a line of upscale flavors designed to win back customers who think ''Here Come De Fudge'' and ''Lunar Cheesecake'' are just for kids.

Almond Amaretto and Grand Marnier are part of the company's new International Creams unveiled Thursday. A third liqueur flavor, Brandied Cherries Flambe, will be added in July.

In the past 40 years, Baskin-Robbins has developed more than 550 flavors, 31 of them offered at any given moment in its 3,200 stores worldwide. The ice cream maker pioneered such flavors as ''Goody Goody Gum Drop,'' ''Chocolate Comet,'' and ''Sweet Corn,'' which is available only in Japan and tastes like corn on the cob. A ketchup flavor couldn't cut the mustard.

The new line also includes non-alcoholic Chocolate Raspberry Truffle and Cappuccino Chip.

Customers won't need identification to buy the alcoholic desserts because the amount of liqueur is so small. The Grand Marnier, with French brandy, is 1.7 percent alcohol, Almond Amaretto has 0.98 percent alcohol content and Brandied Cherries Flambe is too low to measure.

The new flavors are designed ''for the sophisticated, adult palate,'' said Baskin-Robbins President Ron Marley. ''You're talking about people between 25 to 45 years of age.''

''A general comment of people in that age group is that they really liked the store when they were teen-agers, but as they grew up it didn't have the appeal,'' he added.

Baskin-Robbins, once the place to go for premium ice cream, now competes with pricey frozen desserts offered by such makers as Haagen Dazs and Frusen Gladje.

''This made it essential to offer a product not obtainable anywhere else,'' Marley said. ''We've decided to jump over all of them and produce something that is very outstanding and very expensive.''

At a dollar a scoop, the fancy flavors are about a quarter more than the non-alcoholic ones. It cost Baskin-Robbins about $500,000 to develop its International Creams, Marley said.

Baskin-Robbins, a subsidiary of Allied-Lyons of London, had sales of $490 million in 1985, up from $470 million in 1984. Marley said the chain's share of the $15.5 billion ice cream market has remained at about 3 percent for the past six years.

''We haven't lost ground, but we haven't gained either,'' he said.

In addition to a company-record $5 million advertising campaign, Baskin- Robbins outlets will offer free spoon-sized samples of the new flavors, Marley said. ''Our approach will be to station people at the doors of the retail stores and ask people to please try it.''

Marley doesn't think the liqueur-laced flavors will offend the chain's current mix of customers.

''The more we looked at it we thought with only three or four items with alcohol it would not be objectionable,'' Marley said. ''They're not really children's flavors. They really wouldn't be popular with children.''