Shake all ingredients except Peychaud's and strain over crushed ice in a Collins or other tall glass to create a blue layer. Pack crushed ice above that to create a white layer, and top with a red layer of Peychaud's (or Angostura). Alternatively, ignore the red/white/blue thing and the Peychaud's and just enjoy it as a fancy sour.
2 oz Gin, Brooklyn
3⁄4 oz Lemon juice
1⁄2 oz Blue Curaçao
1⁄4 oz Vanilla syrup
2 ds Orange bitters
3 ds Peychaud's Bitters (as garnish)
Pamela Wiznitzer, The Dead Rabbit, NYC.
Gin, Blue Curaçao, Peychaud's Bitters, Orange bitters, Lemon juice, Vanilla syrup