Who Said "Pesto Is The Besto"?

Short answer
"Would you say your pesto is the besto?" is a question asked by Phoebe in season 8, episode 5, of one of the most popular TV shows of all time, Friends.

Long answer
First aired in October 2001, "The One with Rachel's Date" is the 5th episode of Friends' 8th season and sees Monica running her busy restaurant kitchen.

Phoebe pops in to say hi, and as she goes to leave, she bumps into Monica's sous chef. Here's where we pick up the dialogue...

Phoebe: Well, hello there. I didn't see this on the menu.
Monica: Tim, this is Phoebe, Phoebe this is Tim, my new sous chef.
Phoebe: So you're Monica's boss?
Tim: Actually, Monica is my boss, sous is French for under.
Phoebe: Ah, I sous-stand.
Monica: Hey Tim, I need a calamari and a Caesar salad, and could you give me the pesto?
Phoebe: You make pesto?
Tim: Yes, I do.
Phoebe: Would you say your pesto is the besto?
Tim: I don't know but I would say it's pretty goodo!

Friends isn't the only show to shine a spotlight on pesto. Disney's smash hit film Luca depicts the characters indulging in trenette al pesto, while the quote "pesto is the quiche of the 80s" gained fame through When Harry Met Sally.