All of the older stars working with the main cast on this episode were in Twin Peaks.
The first time the Cinnamon Festival is mentioned is in the Pilot episode. Shawn tells Gus that he doubts that he could beat him up because of how their last scuffle turned out. Gus says that it was at the Cinnamon Festival and that he was six and had a cast.
In this episode, Shawn and Gus are invited to a Cinnamon Festival in the town of Dual Spires.
Trivia: Shawn introduces Gus as Lodge Blackman, referencing the Black Lodge (a strange extradimensional space) from the show Twin Peaks.
The name of the murder victim, Paula Merral, is an anagram for "Laura Palmer," the murder victim in Twin Peaks.
Shawn: Detective O'Hara? Shawn Spencer speaking.
Juliet: Did you just use both of our last names? Don't be weird.
Shawn: Do you remember the last email? The one with all the hieroglyphics?
Gus: They were letters and numbers, Shawn.
Gus: These books are archaic.
Shawn: And really old.
Shawn: We're not here to judge you, Mr. Barker. We came to investigate, catch bad guys, and eat pie.
Gus: Not necessarily in that order.
Shawn: And it hasn't been.
Shawn: We started with the pie.
Maudette: Isn't cherry the best?
Gus: The best what?
Maudette: Everything, silly. I thought you were psychic.
Shawn: I am. I'm the psychic. But how did you know that?
Maudette: Word travels. You know, we don't get a lot of gossip around here so an untimely death, a psychic and a black man all in one day. Epic.
This episode is named for (and based on) the 1990's show Twin Peaks.