Silver Fizz
From The Oxford Companion to Spirits & Cocktails
is a variation on the classic Gin Fizz, which brings an extra element of richness (and, reputedly, hangover-reducing properties), thanks to the addition of egg white. See Gin Fizz.
This definition is from The Oxford Companion to Spirits & Cocktails, edited by David Wondrich (Editor-in-Chief) and Noah Rothbaum (Associate Editor).