Marble Cake (voiced by Wayne Grayson) is Mr. Carrot Cake and Mrs. Cup Cake's Nephew who is stepping up to learn the family business, and is proud to be a baker, finding great satisfaction and fulfillment in making delicious treats to make everypony happy. As a hobby, he learns magic but primarily uses it to help with his baking or run errands for his aunt and uncle, as well as make deliveries. He loves his aunt and uncle very much and wants to make them proud. Marble Cake's parents Joffre Cake and Angel Cake live in Canterlot but Marble Cake preferred the close and quiet life of Ponyville and moved in with his aunt and uncle.
- Marble Cake also appeared in Iamnater1225's story, The Magic of Friendship.
- The reason Marble Cake is a unicorn when his aunt, uncle, and parents are all earth ponies is that Marble Cake's great-great-great-great-great-grandfather was a unicorn.