Editorial note: we think the "How to make" should read "...into ice-chilled glass.", not "...ice-filled". This is one of two recipes that has persuaded us that the Martini can indeed be a great cocktail.
Been playing with this one for a few months now. RT below hits the nail on the head; the tequila will dictate the outcome. Use Siete Leguas, Lalo or an equivalent. Try a Reposado. I have found the Italian Martini & Rossi to be the best match (over Dolin, my fav gin vermouth) but dial it down to 3:1. Bitters optional, but absolutely worth playing with. Orange, lemon or grapefruit are all good choices. This is absolutely the best summertime, pool-side Martini I've ever had (I've had a few).
The impression this makes will vary enormously depending on the tequila used. With tequila Ocho it was sublime, with Sauza "Hornitos" it was good but not exciting. I recommend Dolin Blanc, as I don't think tequila stands up to the funkier Italian biancos. It's the same story with gin martinis.
Loved this - I made it with Boker's Bitters in the absence of Margarita Bitters, which worked just finr. A word of warning - strain it into an ice-filled standard coupe as advised and it wont fit! I just slurped and topped it up - all good.