I believe that is where it originates. It's a popular saying in Minnesota thanks to The Mighty Ducks.
1. cake eater 149 up, 41 down
A cake eater actually refers to Edina, MN, saying the people in it are so rich they can have their cake and eat it too. It could also refer to rich white suburban kids in general, too. And BTW- Mighty Ducks was filmed in Minnesota, so he's probably literally calling that kid a cake-eater from Edina.
2. cake eater 42 up, 13 down
In Minnesota this goes as follows:
Usually used as a derogative term for calling a person of wealth a spoiled 'you have it too easy' piece of $hit brat!
Usually called to rich kids who drive BMWs and Mercedes-Benz's and get their college and college housing totally paid for and also get a hefty monthly allowance that's so great that they have absolutely no need to work in order to maintain their lavish lifestyle. This is a cake eater.