Joseph Boroski is a bit of an institution at this point. He’s trained and done the cocktails lists for a lot of the five-star hotels in town, for all of Ashley Sutton’s bars, for Quince, etc.

But the mixology mercenary has finally set up his own shop at the end of a dark, damp alley. In fact, we’re not allowed to tell you exactly where. (Thonglor, odd numbers side, single digit soi, girls in red at the corner.) But you can chat him up on Facebook and he might send you a map.

Is it worth the effort? Well, at B620 it better be. But how does this sound: a Sazerac made with XO cognac and Hudson rye, with a dash of Hella citrus bitters from Brooklyn. You can’t even find half those ingredients in this town!

Nor can you really order this drink: each cocktail here is handcrafted for you only and there is no menu. (In case you’re hyperventilating, a belvedere fizz made with a homemade red basil syrup, fresh lemon, vanilla, and house-made bitter pineapple soda  is “only” B360.)

One last thing: the place’s design is by Ashley Sutton, and it’s absolutely stunning.