Rarity: How does a fabulous pony like me lose to a mare who can’t even remember her own name?  
Derpy: Simple, I have a Master’s Degree in Muffin Making.  
Rarity: Is there such a thing? Besides, your muffin has a bite taken out of it.  
Derpy: It’s to show how good the muffin is. You see, since the muffin already has a bite missing, customers can assume that the muffin is so irresistible, that not even the baker himself or herself could refuse a bite. Clever, right?  
[The crowd agrees with Derpy.]  
——  
Derpy: What is my name anyway?
 
Based on the recent episode, “The Cart Before the Ponies.” :  

 
Rainbow Cupcake by atnezau  
Background from here