They are a side dish that consists of small bits of pale pink corals served in a red and yellow paper food tray. There is also a chili variation of the product. A lot of customers order them with a Krabby Patty.
It is revealed in the episode "Patrick-Man!" that the recipe for toasted coral bits is:
4 cups of coral
1 teaspoon of salt
Mix them together
The price of the coral bits varies between episodes: