When I was in Chicago, I went to a bar with a friend that had $9 espresso martinis and had a good time; so I decided to do a bit here and try to replicate that.
I looked up the menus of every restaurant in Portland that I could think of and some more by googling and checking reddit, and I found a couple that did $9 espresso martinis during happy hour. So, yesterday I checked out both!
The Papa Haydn on 23rd has their happy hour from 3-6pm on weekdays and 3-5pm on weekends; I went yesterday at around 3pm. I ordered a couple of the espresso martinis, and I found they were pretty drinkable -- it's probably a good choice if you wanted to have four in one sitting.
Afterwards, I walked across the westside and a few blocks of the eastside to get to Normandie, who has its happy hour from 5-6pm. I had a couple more espresso martinis and these were definitely more bitter and coffee-forward; I don't think you'd be slamming these back. That said, I got the spiced candied peanuts and those were a highlight, and I appreciated the extra spice on the fries when I walked back to the MAX while eating them (I got them to go).
Overall, I'd possibly do the $9 espresso martini happy hour in the middle of the week -> long walk -> $9 espresso martini happy hour trip again.
Especially if I get to see something like this guy again while making the walk:
