The Pink Flamingo Kid - S3-E17
Mr. Feeny: I'm frustrated to see two young men throw away a friendship.
Shawn: Yeah, well the way I see it Mr. Feeny, you don't need friends. OK, especially friends like him.
Mr. Feeny: Then who do you count on, Mr. Hunter?
Shawn: Family. Your family is always there for you. Come on, Mr. Feeny, a guy like you with no friends, you gotta know I'm right.
Answer: Topanga's middle name is never specified. Considering her sister's name is Nebula Stop-the-war Lawrence, Topanga's is probably something equally unusual.