The specials menu at Red Onion bears a cautionary note: “We regret we are unable to make any changes or return of your dish after serving.” Ostensibly, the warning is for white-bread customers who might be shocked by some of chef Aut “Dang” Boonyakamol’s more daring Northern Thai specialties. But for those of us prepared to push our palates to the limit, the warning might also serve as the kitchen’s insurance against disappointment with the menu’s more mediocre offerings. Red Onion was a runner-up for WW’s Restaurant of the Year in 2009, and some dishes unfailingly delight and impress. The spicy sai oua (Chiang Mai sausage) is a lemongrass-enhanced masterpiece, and standards like the monstrous bowls of tom yum soup are the best in town. But those who stick with insiders’ advice and order from the rotating specials menu could also come up short. The neau yang mamprik jaiw (marinated steak) underperforms in the flavor department, and the house special seafood curry, while highly competent, provides no surprises. Take into account the lackluster service, and it becomes clear that at least part of Red Onion’s stellar reputation is due to a dearth of high-quality Thai places in town. But the highlights still keep us hungry for more.