Hayward's in Nashua has it all the time, when they are open (Other locations may not). It's a bit pricier than going to the supermarket, but it's also better.

Kimball Farm has it too - probably at all of their locations. Jaffrey is convenient for the monadnock region, and Westford MA isn't too much of a drive from south central. If you've never been to the Westford location, it's a complete zoo. Just a warning!