Luke Johnson, "Louie Gohmert Goes Off On Eric Holder At House Hearing", Huffington Post 5/16/2013:
A visibly infuriated Rep. Louie Gohmert (R-Texas) tore into Attorney General Eric Holder after his time expired in a House Judiciary Committee hearing Wednesday. […]
"I cannot have a witness challenge my character," said Gohmert, as the chairman told him again that his time had expired. Gohmert continued talking as other members of the committee asked him to observe hearing rules and suspend.
Gohmert asked again for a point of personal privilege and said that Holder was "wrong on the things that I asserted as fact." The other members of the committee disputed that his contention was a point of personal privilege.
"The attorney general will not cast aspersions on my asparagus," said Gohmert, in a malapropism for the ages.
Here's the audio from the crucial passage, beginning about 4:10 into the C-SPAN clip embedded in the HuffPo story:
I can't make out anything (of the crucial phrase) except "…((cast)) aspersions on my asparagus".
When I first heard this, I wondered whether it was some kind of down-home idiom. But I haven't been able to turn up any evidence for this view, so apparently it's just an unexpected Fay-Cutler malapropism for "cast aspersions on my character".
Update — In the comments, Dick Margulis and Jon Weinberg present evidence that this was in fact an idiom choice and not a speech error; and Cameron Majidi locates the locus classicus (though of a slightly different form of the joke).