Hey hey! ^^ I've made up a suggestion plan for this waffle cosplay you're hoping to do. I used the same technique to do my Pikachu cosplay. I hope it's understandable, and that it can help you someway.
I added a little of what Vondan-San said, thanks to you! *hugs*
- Side note - if you're doing the Sandwich style, do a little of the waffle look on the inside of you too, just in case people can see your wire-cable insides!. Only if you'd like ^^
You mentioned a pat of butter XD
Take a slab of yellow foam, or if you're really ambitious, make it a yellow cloth cover and stick some velco on the back. Have a few velcro 12-set tabs in your pocket or something. *chuckles*