See the short article on Mint Julep for the more modern and popular bourbon mint julep.
MINT JULEP RECIPE
Pearl Street House, Louisville, mid 19th century
"Take a large and deep cut glass tumbler, fill it with sufficient sugar and ice to the brim -- half of the ice shaved into snow and the rest in lumps of moderate size.
Lay on the top of it three fresh leaves of mint without any part of the stem attached.
Pour on just half a glass of fine, unimpeachable cognac brandy, than just half a glass of fine old Jamaican rum; then add half a glass of old ripe port wine.
Then pour the mass rapidly for some time, back and forth into tumblers; the longer this action continues the better.
Then plant a small bunch of mint on one side of the tumbler by putting the stems down into the ice, and having the leaves up about as high as the nose of the drinker should come."