Frisco Sour

History

The Frisco Sour started life as a mere "Frisco", sans Sour, in vintage tomes including William "Cocktail Bill" Boothby's 1934 The World's Drinks And How To Mix Them, Lucius-Beebe's 1946 The Stock Club Bar Book, and David A. Embury's 1948 The Fine Art of Mixing Drinks.

FRISCO
Whisky............... ¾ jigger
Benedictine........ ¼ jigger
Stir well in bar glass with lump of ice, twist lemon peel over top and serve with spoon and ice water chaser.

William Boothby, The World's Drinks And How To Mix Them, 1934

Frisco Cocktail:
2 oz bourbon
¾ oz Benedictine
twist of lemon peel
Stir and serve in 3oz. cocktail glass.

Lucius-Beebe, The Stock Club Bar Book, 1946

FRISCO
2 parts Benedictine
1 part Lemon Juice
6 parts Whisky
Shake or stir with cracked ice. In some recipes the lemon juice is omitted.

David A. Embury, The Fine Art of Mixing Drinks, 19448

The original Frisco is a tad sweet and is much improved with a dash or two of orange bitters to bolster the lemon oils from the twist. This obviously led a bartender somewhere to add citrus juice. In Stanley M. Jones' 1977 Jones' Complete BarGuide, he lists the above Frisco followed by a sour version.

FRISCO
Cocktail Glass Stir
2 oz Bourbon
½ oz Benedictine
Lemon twist

FRISCO SOUR
Sour glass Shake
½ oz lemon juice
¼ oz lime juice
¾ oz Benedictine
1-¼ oz whiskey
¼ tsp sugar
Lemon wedge, lime wheel

Stanley M. Jones, Jones' Complete BarGuide, 1977

Once this cocktail morphed into a sour, the addition of egg white was a natural progression, which I believe came in the 1990s, when this was a popular cocktail in London's bar scene. That's when I first encountered the Frisco Sour, then served on-the-rocks. However, it also works well, as per Jones' recipe, strained into a stemmed sour glass or coupe.