I misread the ingredients and made with Galliano vanilla instead of L'Autentico (which sadly isn't available where I live..)
It still made a remarkably good 3 ingredient equal measures drink though!

martini R | Wolcott (TW) - sweet. plain. cant really taste the galliano. but its straight and clean. lemon squeeze is a nice mix. evocative of Trix cereal. i think i want more booze, perhaps less galliano as another commentator said. maybe even serve it on the rocks.

I’ve just build this, but in a whisky glass with an ice ball. And orange twist insteadmof lemon but that was just a mistake, not an intentional insult to the récipe. But the orange sit well, so did the ice. Very good to my taste.

came back to this fine cocktail on a sunny copenhagen autumn afternoon.
25 ml Galliano L'Autentoco
30 ml Four Roses Singke barrel bourbon
30 ml Chazalettes Rosso
It came out just perfect (i.e. a little less Galliano than in the spec)
Do try it, enjoy it.

Needs to be thoroughly stirred and consequently diluted, otherwise it gets a bit stickily sweet as it looses the chill.

The original recipe calls for Vya Sweet Vermouth. I prefer it in this cocktail.

I tried it both with Bourbon and Rye. For me, the Rye had it with the Galliano more held in check.

Nice variant of a Manhattan - definitely with taste of Galliano but it does mingle well here. Anyway, I might try with a little less Galliano next time - or a more dominant and bitter red vermouth.