It's from Media Matters, looking for confirmation:
Glenn Beck's long history of vicious personal attacks
Beck reportedly ridiculed rival's wife for having a miscarriage. Salon.com's Alexander Zaitchik quoted a former Beck colleague describing an incident in which Beck was outraged over a rival radio host criticizing a Beck gag. Beck reportedly responded by calling the rival host's wife on air and ridiculing her for having a miscarriage:
I used to listen to Beck on and off but was never really a fan. One day I heard him say something so horrible that I swore I would never listen to him again. Anyway, it was near Christmas few years ago and I really don’t want to share this because it is so bad what he said. Beck and his lackeys were joking about stuff and the topic of Christmas cookies came up. They mentioned Santa Christmas cookies and someone said, why not make a Jesus Christmas cookie (I think what was said was a baby Jesus Christmas cookie). I am pretty sure someone said that a Jesus Christmas cookie could double as a communion wafer. I know I heard Glenn Beck say that making a Jesus Christmas cookie would not be a good idea because “that would be putting a Jew in an oven.”
I know what I heard - I was flabbergasted and stunned. That seemed to be a quick throwaway joke that was almost lost in the banter. No one talks that way unless they are really depraved. I think Beck does have a mental problem where he says things without thinking but I can’t give him a pass on a “joke” like that. If mean and perverse garbage like that is at the top of his head who knows what is deep down, then?