What we have here is a Perfect Martini (gin and a 50/50 blend of sweet and dry vermouth), with the addition of orange juice. Created around the turn of the 20th century, here’s what cocktail author Albert Stevens Crockett has to say about its origin:
“We had a cocktail in those days called the Duplex, which had a pretty fair demand. One day, I was making one for a customer when in came Traverson, head waiter of the Empire Room–the main dining room in the original Waldorf. A Duplex was composed of equal parts of French and Italian Vermouth, shaken up with squeezed orange peel, or two dashes of Orange Bitters. Traverson said, ‘Why don’t you get up a new cocktail? I have a customer who says you can’t do it.’
‘Can’t I?’ I replied.
Well, I finished the Duplex I was making, and a thought came to me. I poured into a mixing glass the equivalent of two jiggers of Gordon Gin. Then I filled the jigger with orange juice, so that it made one-third of orange juice and two-thirds of Gin. Then into the mixture I put a dash each of Italian and French Vermouth, shaking the thing up. I didn’t taste it myself, but I poured it into a cocktail glass and handed it to Traverson and said: ‘You are a pretty good judge.’ (He was.) ‘See what you think of that.’ Traverson tasted it. Then he swallowed it whole.
‘By God!’ he said, ‘you’ve really got something new! That will make a big hit. Make me another and I will take it back to that customer in the dining room. Bet you’ll sell a lot of them. Have you got plenty of oranges? If you haven’t, you better stock up, because I’m going to sell a lot of those cocktails during lunch.’
The demand for Bronx cocktails started that day. Pretty soon we were using a whole case of oranges a day. And then several cases.
The name? No, it wasn’t really named directly after the borough or the river so-called. I had been at the Bronx Zoo a day or two before, and I saw,of course, a lot of beasts I had never known. Customers used to tell me of the strange animals they saw after a lot of mixed drinks. So when Traverson said to me, as he started to take the drink in to the customer, ‘What’ll I tell him is the name of this drink?’ I thought of those animals, and said: ‘Oh, you can tell him it is a “Bronx”.'”
The key here is to use fresh squeezed juice (not from a carton or can) and keep the gin/juice ratio equal. Too much orange and it quickly loses character and becomes too sweet. As it is, this is an easily quaffable beverage perfect for the beginning of an evening’s festivities.
0.5oz dry vermouth
0.5oz sweet vermouth
1oz orange juice
Garnish: orange wheel
Shake with ice and strain into chilled cocktail glass. Add orange wheel.