Cynar has been suggested as a substitute.

Original published recipe used Townshend's Kashmiri amaro which is no longer made. It was a "Bitter Tea Liqueur" described as "Assamese black tea and piercing Indian spices like cardamom and black pepper, alongside savory Italian herbs and roots."

Note that while the recipe in the book lists 4 dashes of bitters, the dasher bottle used in the video would likely only dispense about 1/2 of a "normal" dash, so the recipe here reflects that as 2 dashes.

Perhaps 1 oz each of Malört and Bourbon would work well here too for a slightly less bitter-herbal balance or adjust to your preferred bitterness level.

Mythology Distillery lists this cocktail as using "house whiskey" which is not specified. It might be their American Whiskey blend of rye (95% rye), a high rye bourbon, and a wheated bourbon. I used Bulleit bourbon.

Foro amaro is often used in Black Manhattan riffs in place of Averna, but the oloroso sherry in this particular cocktail elevates and deepens the rich flavor.

Curator's note: There is an older, unrelated tequila cocktail with the Viva Maria! name, so the one here has been renamed to #2 per the suggestion of the latter's creator.

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.