Stir with ice, strain into cocktail glass. (Historical cocktail called for shake, I don't recommend doing that.)
Khoosh bitter was established in 1882, went through liquidation in 1900, but was still selling product until it went defunct sometime before WWII, with the last advertising seen in 1937. It has been revived/re-imagined by Phoenyx Spirits in 2022/2023.
The current iteration of Khoosh is a 40 proof orange bitter amaro, with turmeric for color; cardamom, anise, black tea and Indian spices for flavor; quassia amara as the primary bittering agent: and an infusion from a mix of citrus peel, including kumquat.
The Monkey Island recipe from 1937's Cafe Royale Cocktail Book is:
1 dash Khoosh Bitters.
1/4 Bullace Gin (bullace is a fruit related to sloe or damson.)
1/4 London Dry Gin.
1/2 French Vermouth.
Alterations:
I have used 1/4 oz of Khoosh in the altered recipe, to account for possibly higher strength and bitterness of original, and ill defined/larger dashes often used at the time.
Substituted Averell damson gin for bullace gin--a good sloe gin would also work.
Noilly Prat Dry "original dry" (hard to come by in the U.S) rather than the extra dry that has replaced it. Reduced the vermouth from ~1/2 the drink to little more than 1/3 while boosting the others.
Originally published in the 1937 "Cafe Royale Cocktail Book" by W. J. Tarling. Ratios adjusted for modern ingredients and tastes.
1937 "Cafe Royale Cocktail Book" by W. J. Tarling