Copperstill Bar at Jaragua
This is a great, still pretty undiscovered bar at the back of Jaragua Salvadoran restaurant on Beverly in Koreatown. (It's got a separate entrance under the sign just east of the Jaragua entrance). The bartender Nancy Kwon is making intricate craft cocktails using things like house made tamarind, peach infused vinegar and all of the other trappings of modern mixology. She makes both classics and new spins on things, and the care she puts into every cocktail is pretty amazing.
You can order off the excellent Jaragua menu at the bar, but now they also have a bar menu with things like Salvadoran poutine (with yuca sticks instead of fries) and pan con pavo sliders. I didn't try the new bar menu yet since I'd already eaten when I went there, but I definitely will next time I go.