Here's the perfect scoop for a hot day:

Ha agen-Dazs, the trendy chain of ice cream stores, agreed yesterday to be taken over by Pillsbury Co.

The giant Minneapolis-based food company would not say how much dough it will pay for Ha agen-Dazs--which, despite its Danish-sounding name, traces its origins to a New York pushcart, makes its ice cream in New Jersey and is based in the Bronx.

Fast-growing Ha agen-Dazs, which had sales last year of about $115 million, started franchising its stores in 1976 and now has 244 stores around the country selling the company's high-quality, high-priced ice cream and sorbet. The products are also available at many food stores.

Pillsbury Chairman William H. Spoor said the company hopes to open new Ha agen-Dazs stores at the rate of about 150 a year. "Our plans for the company are to grow it," Spoor said in an interview.

Spoor said that Pillsbury--which in recent years has expanded beyond flour and packaged foods into such products as Green Giant canned vegetables and frozen foods, and Burger King and Bennigan's restaurants--considered 8,000 possible acquisitions in the food business before narrowing its list to 21 and, finally, choosing to make an offer to buy Ha agen-Dazs. "You don't find them like this very often--this kind of quality," Spoor said.

Ha agen-Dazs was founded in the early 1960s, an outgrowth of the Mattus family's Italian-ice business in New York. The Danish-sounding name--which has no meaning--was adopted in an attempt to give the ice cream the sound of a quality product. Ha agen-Dazs officials have claimed in interviews, however, that the process for making the ice cream came from a friend of a friend of Reuben Mattus who was in the ice cream business in Denmark.