I think this was originally a recipe from Jamie Boudreau in Seattle.

http://spiritsandcocktails.wordpress.com/2007/08/13/mxmo-orange/

Thank you for pointing this out. I've corrected the recipe and updated the attribution.

This is very nice. Is it your creation?

I'm not sure where I got this. I probably was from an online forum.

It looks like this is a variation of a Duplex. I stumbled upon this- I wonder if this is where you saw it too: http://chowhound.chow.com/topics/636481. In any case, it is a lovely drink that I keep coming back to with various modifications...

I don't know, but probably. I'll give DavisSqPro credit.

<br />The Duplex is an enjoyable drink, and its wonderful taste is in the simplicity of the drink itself. There are only two major ingredients, the Lillet Blanc and the Punt e Mes. Period. The other two ingredients may seem to play a somewhat minor role, but they are essential to the drink's pleasantness. The orange bitters (I used Fee Bros West Indies Orange Bitters, which has a somewhat more distinctive taste than the usual Regan's or Angostura Orange Bitters) and the lemon peel add additional flavors and more complexity to this drink. The Duplex can, in my opinion, be imbibed in a hot afternoon, or before dinner, or after dinner. It is a light, somewhat complex tasting, yet versatile drink.

refreshing and tasty like a Picon punch -- I'll probably fiddle with ingredients. I topped it with a short blast of soda water for texture, and a little astringency.

Curated to move brands from notes to Brands (Fee's, Noilly Prat, Partida)

I had this first at Brick & Mortar in Cambridge, Massachusetts (Misty Kalkofen's place) but it was mezcal instead of tequila and it was 1:1:1 mezcal, vermouth (perfect as here), and campari.

I make the mezcal version of this at home with Gran Classico instead of Campari and it is among my very favorite cocktails in this modified form.

This recipe seems under-rated. I wonder if it is the ratio or if people are using cheap/terrible sloe gin?

There are, at least, three types of cocktails that vye for the "Blackthorn" name. Sloe berries are the fruit of the Blackthorn tree & this concoction is probably the one that should have the title [though other have (humorously) proposed Irish whiskey-based concoction being credible due to where Blackthorn trees are grown].

This recipe dates to pre-1926 [when it appeared in Bolton's Sideboard]. Dave Arnold's recipe [1.5 oz Plymouth/0.75 sweet vermouth/0.75 sloe gin/2 dashes bitters] is better-balanced than this version.

<br />I tried the revised "Blackthorn English" recipe submited by commentor noksagt. I used Plymouth Gin, Hayman's Sloe Gin, Dolin sweet vermouth, and Bitter Truth's aromatic bitters. Personally, I did not find this particular cocktail to be well balanced. I don't know whether Hayman's sloe gin is considered a better brand, but I thought it overwhelmed the rest of the ingredients. If I were to make this libation again, I would probably turn to Cinzano's sweet vermouth, which has pronounced fruity overtones thatmay soften the sloe gin. Also, noksagt did not specify the type of bitters to us; in the future I will probably fall back on orange bitters. Regardless, I rated noksagt's suggested version of "Blackthorn English" at 3.0.

So this was one of those original drinks on KC that I  ran across and saw it was in need of fixing. The earliest I can trace this back is to a 1901 private "Sideboard for Gentlemen" published for the St. Boltoph's Club in Boston, MA. It's been around since 1880 and had members including Henry Cabot Lodge, Francis Parkman and Phillips Brooks (who wrote the lyrics to O Little Town of Bethlehem). Thanks,  Zachary

Curated to correct recipe and attribution as per http://www.cocktailchronicles.com/2006/08/01/test-pilot/

YUM!! This is such a great drink, the absinthe is rendered unrecognisable but brings out the cinnamon flavour of the falernum, how is that possible? I don't know but it sure is tasty! Also don't go flying any planes after one of these, this sucker's strong!

I always call this the Alto Cucina by Stephen Shellenberger that was published in the May/June issue of Imbibe Magazine. Orange twist though.
https://kindredcocktails.com/cocktail/alto-cucina

Recipes specifically calling for Old Monk are so few and far between, I had to give this one a spin. The full ounce of Punt e Mes beats back most of the rye nuances and even most of the endearing harshness of the Old Monk. Certainly the Bénédictine comes through loud and clear. Successive sips do reveal more of the base spirits' character, but they definitely play a backseat to the Punt e Mes and Bénédictine.

I might need to revisit this one with good old Noily Prat to try to strike a rum/rye/vermouth balance that is more to my liking, but this is one that is worth further reflection and experimentation.

When we had it at Drink in 2008, it was 1 dash Mole Bitters. The cinnamon note of the Fee's would be delightful, but it was not the house recipe (the version of the Drink recipe book I have lists it as 2 dashes Mole Bitters and served in a rocks glass without ice).

http://cocktailvirgin.blogspot.com/2008/11/1919-cocktail.html

I now work at Drink, and it is made with 1 dash mole bitters and no garnish now as it was back in 2008. As per my blog and per the Drink bar bible. Everything else is a variation.

Got it, thanks Fred. Zachary

Surprised that it doesn't have a cherry garnish. A bit too close to a Manhattan - will try increasing the rum/rye balance.

When I was working at Drink, it was discussed how if there were to be a garnish, nutmeg would be the one. It has enough body that a sweet cherry would be superfluous. In my mind the 1919 is an expansion of the Fort Point Cocktails at that bar (double the Punt e Mes and Benedictine amounts and split the rye with Old Monk Rum) and starker form gets a cherry garnish.
https://cocktailvirgin.blogspot.com/2008/10/fort-point-cocktail.html

I feel like I had this at No 9 Park and it pre-dated the Fort Point, but maybe I am misremembering... it was part of the Old Monk craze of that era.

It was not on the menu at No. 9 Park right before or after Drink opened in October 2008. There's a chance that Ben Sandrof had been tinkering with it before Drink finally opened, but I have never seen a reference to that possibility (including my own time spent in that establishment), and it has always been spoken of as a Drink house original. Then again, this is history told in bars by folks that drink.

yeah, didn't mean to imply it was on the menu, just that I had it there

Reduce Punt e Mes to 0.75 oz, bump up rum to compensate. Worth trying over a large sphere.