Amaranth

Old Waldorf Bar Days by Albert Stevens Crockett (1931) — Old Waldorf Bar Days 1931, opening cocktail appendix

1. Stir and strain, fill from siphon, add a little powdered sugar, and serve while foaming.

The Old Waldorf-Astoria Bar Book by Albert Stevens Crockett (1935, p.36)

1. Stir the bitters, whiskey, and ice.
2. Fill from siphon and add powdered sugar to taste before serving.

Ice: Ice