I think my favourite is the scene in The Bell Jar where Esther eats an entire bowl of caviar with avocado just because she can.
The grocery store scene in Linda Jaivan's Eat Me is hilarious. I can't say "lurve blender" without giggling.
Then there is the part in Chuck Palahniuk's Haunted with the tattoo (if you have read it you will know what I mean). And a similar thing in Dexter is Delicious by Jeff Lindsay which gave me the shivers.