It's the song title & lyric that follows the line "When the moon hits your eye like a big pizza pie..."
In 
Look Before You Leap, Frasier is attempting an opera song, requiring him to hit 
.... his love of puns both on and off of What's My Line, and since he was the one 
who... [DOC] [TLE] The Top 10 Best Blogs on Amor - Notey [PAR] When the moon hits your eye like a big pizza pie, that's amore.