The first rule of Double A is don’t talk about Double A (it’s just rude, since most of your friends aren’t going to get in anyway). The second rule of Double A is don’t bother showing up unannounced (more on that shortly). The third rule of Double A is if you do gain entry to this chichi cocktail lounge on the lower level of the River North restaurant Mercadito, don’t go hungry. Otherwise,the thought of all those tilapia tacos being assembled in the kitchen nearby will drive you mad.

But back to rule two: Before my maiden visit, I had read that Double A’s manager, Victor de Leon, described the bar as “the toughest door in Chicago.” Worried my two friends and I would be turned away, I e-mailed ahead to see if we could snag seats at the relatively early hour of 11 p.m. De Leon replied that we were welcome to stop by for a drink before the night’s bigger parties arrived. In theory, the bar’s exclusivity comes as much from its size—65 seats—as from some inflated sense of superiority. And yet: “For future reference, we recommend bottle service for parties of six or more,” de Leon wrote.

Fast-forward to Saturday. As my friendsand I stood quietly in the dim hallway, waiting for our reservation to be verified, we couldn’t help but comment on the bass booming from behind the bar’s massive front door—or on the square peephole, which at one point slid open to reveal Mercadito’s chef/co-owner, Patricio Sandoval, peering out at us. Soon de Leon appeared and led us inside to an expansive leather booth. As a DJ spun Black Eyed Peas, I noticed a sequin-bedecked Bright Young Thing getting frisky with her date at a table full of chic 20-somethings. De Leon followed my gaze. “One of them just moved here from New York,” he said. “They’re celebrating. They ate a big meal at Mercadito, and we invited them to come on down.”

Nodding, we turned our attention to the custom-cocktail menu, then watched as our drinks were whipped up at the counterlike bar—the room’s central feature. I ordered the Onawhim ($14), selecting vodka as my spirit of choice and letting the bartender do the rest. The fruity drink she dreamed up just for me delivered a rush of fresh cucumber every time I raised my glass. Delicious—but it takes a while to turn out a cocktail that has as many ingredients as an entrée, which meant long lags between our drinks’ arrivals.

“Now they’re making out like the plane’s going down,” my friend Kevin said, gesturing toward Miss Sequins and her paramour, both of whom had let their inhibitions slip out that heavy front door. We stared unabashedly, then flagged down de Leon for some tacos. “Sorry, they’re only served upstairs,” he said. Figuring our Double date was at its close, we climbed up to the restaurant, claimed three barstools, and ordered one more round. “And could we please see a menu?” I asked.

GO: DOUBLE A
108 W. Kinzie St., lower level; rsvp@doubleachicago.com