The Gold Cadillac is the signature drink of Poor Red's, a bar in El Dorado. It was "invented in the 1950s for two customers bound for Lake Tahoe and matrimony" (Landmark for sale — as it is, 7/21/2006, Sacramento Bee/M.S. Enkoji).
The ingredients include "sweet Italian liqueur Galliano, white creme de cacao, Half and Half, and ice, all whipped into a froth with a blender."