Good·fellas thin (noun): Measurement of a slice of garlic cut extremely thin using a razor blade.
Throughout Andrew Carmellini's cookbook Urban Italian (2008), recipes repeatedly call for garlic cloves to be sliced "Goodfellas thin."
The term is a reference to a famous scene (see below) in Martin Scorcese's 1990 film Goodfellas, in which lead character Henry Hill (Ray Liotta) describes in detail how mob boss Paulie Cicero (Paul Sorvino) prepared dinner while in prison:
"In prison, dinner was always a big thing. We had a pasta course, then we had a meat or a fish. Paulie was doing a year for contempt and had a wonderful system for garlic. He used a razor and sliced it so thin it would liquefy in the pan with a little oil. It's a very good system."
In an interview with Gothamist, Gwen Hyman, Carmellini's wife and Urban Italian co-author, in describing the writing process, recalled, "We were slicing garlic and I asked how thin. See-through thin? I asked. And Andrew just said 'Goodfellas thin.'"