Buster Clusters

Buster Clusters are the homemade chocolates that Buster and Arthur made in "Buster's Sweet Success" to make up for the chocolates Buster was supposed to sell, but ate instead. Many people bought it, including their school principal, Mr. Haney. All of the customers eventually found out that the chocolate tasted terrible, and they wanted their money back. In the end, they became prank chocolates in Jack's Joke Shop.

Ingredients
Arthur and Buster attempted to use the ingredients listed on the back of the actual chocolates, but they substituted some things and ruined the chocolate. Instead of soy lecithin, they used soy sauce. For the egg whites, they used egg shells (because the shells are white). Since it called for a fruit, they added tomatoes, since they are fruits. Other ingredients include nuts and cinnamon.

Jack's Joke Shop
Jack, the owner of Jack's Joke Shop, sees the people complain about the bad taste. A long-time supporter of the school band, he offers to pay back the money Buster owed, if Buster worked in his store for a few Saturdays. Buster presumably also gave Jack the recipe so that he could sell Buster Clusters as joke candy, since it tastes terrible. It is uncertain if Jack still sells them, as it was discovered that Buster Clusters will turn your tongue black and give you a rash.

Arthur

 * 602b. "Buster's Sweet Success"
 * 709a. "Prunella Sees the Light"

Trivia

 * One question in The Brain's Brain Game refers to these as "Buster's Clusters".