Intuited from Lafcadio Hearn's late 1880 description, which inventoried the ingredients but only hinted at amounts.

Ingredients

• 1
  oz
  of Genever (Dutch/Holland Gin)
• 5
  oz
  of Coconut water
• 1
  piece(s)
  of Egg
• 0.5
  oz
  of Powdered sugar
• 1
  dash
  of Freshly grated nutmeg

Steps

• Put coconut water, spirit, egg and sugar into a bowl. Add a generous amount of grated nutmeg. Swizzle or whisk until you've worked up a good froth, then pour into a pre-chilled glass (no ice). Top with a little more nutmeg.