I realized as I was about to post this someone had already asked favorite scene, but I figured I could still do a more specified version still? It might be because my entrance into this was MessyFun, but even today, it's usually the argument/pie fight style, which seems to be on the way out in terms of a style. Lenny used to traffic in that style heavily.
If I had to go old school, I would say "Ariel's Pie Shop". It's got the dialogue and back-and-forth that keeps it good throughout.
Newer? I have to go the "Tuesday v. Gia" scene from MessyGirl (I always felt bad I discovered the site too late to have a custom for a sequel ), or "The Pie Convention" with Amy and Penelope.