New Orleans Gin Fizz — The Cocktail Ontologist

Family

Harry of Ciro's ABC of Mixing Cocktails by Harry of Ciro's (1923, p.63) — Harry of Ciro's 1923

1 lemon	lemon juice — Lemon	acid
1 glass	gin	base
	Soda water — Syphon	dilution
0.5 wineglass	cream — Fresh Cream	other
1 white	egg white — White of Egg	other
2 dashes	orange flower water — Fleur d'Oranger	other
1 teaspoonful	sugar	sweetener

This matters because it gives the 1923 London book a full cream-and-orange-flower New Orleans fizz checkpoint.

The long shake, cream finish, and orange-flower seasoning are the defining service details.

Peychaud's New Orleans Cocktails by John Held Jr. (1935, p.6)

0.5 lemon	lemon juice — Lemon juice	acid
1 jigger	dry gin — Dry Gin	base
1 tablespoon	sugar — Granulated sugar	base
2 ounces	cream — Cream	other
1 unit	egg white — Egg white	other
	ice — Ice	other
2 dashes	orange flower water — Orange Flower Water	other

Combine all ingredients with plenty of ice and shake until the mixture becomes very creamy and the ice no longer tinkes against the shaker.
Strain into a thin glass and serve.

Ice: Ice

The booklet emphasizes that this must be shaken much longer than an ordinary fizz to count as a real New Orleans version.

See also: Morning Glory Fizz, Gin Fizz