How the Cookie Crumbles is the first part of the twentieth episode of Arthur Season 2. How the Cookie Crumble aired on May 25, 1998. It aired with the episode "Sue Ellen's Little Sister".
Muffy is having difficulty coming up with a recipe so her friends make a joke recipe, which turns out to taste delicious and she takes all of the credit. Her friends are angry and refuse to be friends with Muffy until she gives them the credit for helping her.