I used Plymouth Navy strength gin and a tiny pinch of kosher salt and wow, this is an incredible cocktail. The interplay of the two monastic liqueurs and the lemon juice is sublime with the gin bringing a nice backbone.

With both Simon and a number of experienced drinkers rating this highly, I may be sticking my neck out a little by suggesting a small adjustment that worked better for me.
I found the following ratios more balanced:
37.5 ml gin
15 ml Yellow Chartreuse
15 ml Bénédictine
22.5 ml lemon
In this more spirit-forward build, the gin clearly leads. The Chartreuse is present but controlled, while the Bénédictine adds a subtle honeyed background note. The lemon brings brightness without tipping into excess acidity.
Just sharing in case it’s helpful to anyone experimenting with the balance.

I wouldn't use subs here. Strega and Drambuie left me wanting the call ingredients. Tried it twice, leaving the lemon measure as is, and 25:20:15 with the spiritous elements left a more approachable taste, but not quite balanced. Ran out of the Benebuie, so I'll have to wait to dial in the delivery.

Very well balanced drink overall, and one of my favorites. For a more citrusy profile, I use Citadelle gin. Though I love the sweetness in Chartreuse Jaune, Chartreuse Verte adds a much more herbal backbone and accents the juniper notes in gin.

This for me was an all encompassing lemon bomb. Might try again with half the lemon juice. Also I used Dolin Génépy. Perhaps Chartreuse Jaune is more assertive here.

Really tasty/tart/lemony drink! 2 drops saline will tone down the sweetness.

Some drops of saline solution add a nice extra. My next try will be Japanese Umami bitters.

Excellent. Be generous with the gin, it easily gets lost amongst so many assertive ingredients.

Magic. The kind of alchemy that great cocktails are all about.

I used The Botanist gin. All flavors in perfect harmony.

Great cocktail. I subbed B&B on one round and made it with Dolin Genepy de Chamois and loved it. The B&B cut the sweetness that others observed.

With Tanqueray 10 really outstanding. It may remove Monte Cassino from my No.1 cocktail position. Chartreuse shines more in this version. There is also another variation with calvados which is very delicious: Widows Word.

Absolutely delicious but over sweet…would reduce Benedictine by 1/4oz to allow the slight bitterness of the Yellow Chartreuse to come out.

For Last Word Lovers, this is my go-to when limes are not around, or ridiculously expensive.

Yes, this is an excellent, well balanced drink. Perhaps slightly on the sweeter side with the Benedictine, but it works well. Definitely in the rotation.

I don’t have Yellow Chartreuse, but I used Genepy L'Ancienne instead and added a barspoon of Elixir Végétal to enhance the complexity—it worked perfectly!

This terrific. Balance is excellent, the herbal notes do not overpower the gin and lemon

It is a "Monte Cassino" with Gin instead Rye whiskey. Very interesting Idea

Swap the Benedictine out for Americano Blanco and you have an Embassie. Can't wait to try them side by side.