Or "special" - "You didn't miss Karen's special cookies, did ya?"
That would usually be coupled with a very veiled reference to how she put in the minimum possible effort while indirectly insulting her entire bloodline: "Oh, don't you just feel for Karen? I don't know how she gets anything done with those kids of hers."
Alternatively, if the speaker wants to embarrass her in front of someone with a higher social standing; "Karen, these cookies are just the best thing ever! What do you put in these to make them so good?"
It's "Karen" in normal conversation, but if she brought storebought cookies to the potluck it's "Kar-in-nuh", with the emphasis on the last syllanble.
In my head, these are called "spite syllables" :)