I FIRST COVERED Sok Sab Bai in August of last year, when it was a cart in a lot behind a Burgerville off SE Hawthorne ["Building a Better Banh Mi," Last Supper, Aug 16, 2012]. The guy in charge of the food was slinging with real passion; vast bowls of elegant, jeweled soups flew out the window alongside irresistible plates of char-grilled meat. One of the best Asian baguette sandwiches in town—the nom pang-sighk—could be yours for $5. This April, the respected Cambodian cart took up residence in the location of the owner's former restaurant, Bara Sushi, and its ever-changing menu took root and found stability.

In its new shoes, Sok Sab Bai is an intimate neighborhood restaurant, easily at home in a cleanly converted old house next to St. Jack. The food has taken on an added dimension of beauty now that Chef Nyno Thol has moved beyond plastic trays and Chinet: The plated compositions are almost zen-like, with artful fronds of fragrant herbs and colors that pop. The hearty but delicate soups and sizzling meats that made the cart an institution are still there, but the overall tone of the menu favors refinement and quiet flavors over the more primal stuff that put them on the map. It's solid stuff with shining moments, but I feel it's holding back in many places and I don't know why.

Krueng beef ribs ($15) are the soul of the old spot: dark, cross-cut beef short ribs, marinated in a complex sweet ’n' spicy sauce, are some of the most primally mouth-watering pieces of beef in town. The tender, grass-fed beef is charred, caramelized, dynamic, and plentiful. When dipped in Thol's aromatic proprietary "Da Sauce" fish sauce, the already pitch-perfect meat is transformed into a higher plane of umami and flavor. It is as good as grilled meat gets.

Ginger fried bass ($16) is another bold item that works beautifully if you're a fan of whole fried fish. The visual of the curved creature, served upright and doused in a salty, fully flavored sauce of ginger and pungent fermented soybean, artfully evoked a freshwater still life. The meat was moist throughout, with the texture perfectly set at the bone, and every inch of skin was crisp.

Khwa ko ($13) needs to be checked off the bucket list of any charcuterie enthusiast. The fermented beef sausage gets a thick crust from char-grilling, which creates a satisfying chew against the juicy, slightly tangy interior. Like all entrées, it's served with steamed rice, pickled vegetables, a delicate fermented slaw, and the addictive Da Sauce (which Thol has had the good business sense to bottle and sell).

Nom pa chok ($12) was the standout among the soups. Generous morsels of tender, dark-meat chicken, slow-cooked carrots, potatoes, and noodles fill a bowl of fragrant coconut-based curry. The low and sweet flavors pivot off the richness of chopped peanuts, and shrimp paste gives the broth backbone without coming off strong.

Those are the hits. Salaw machu krueng ($12), a "hot and sour"-style soup of braised beef, tomatoes, long beans, jalapeño, and tamarind broth, is one of those authentic dishes that just doesn't seem to press the right buttons on the American palate. It's balanced and flavorful, but the ingredients seem more like homework at Grandma's than an exotic and escapist meal out. Any mention of Asian fried chicken wings should prick the ears of a Portlander, and prick Nyno's Spicy Wings did. It was three wings for $13, though, and the petite joints were quiet affairs, distinctly lacking the bombastic one-upsmanship of the Pok Pok benchmark. A starter of plee-uh sighk ko ($7) is an interesting ceviche of beef with radish, peppers, chopped peanut, and mint, but the flavor was mainly lime and the faint sweetness of bell pepper, and would have been more interesting to my perhaps jaded palate with more emphasis on the mint and peanut. Pork belly buns ($6) were built nicely, but featured pure fat and chewy rind, and "caramelized tofu" ($4/happy hour, $9/lunch, $10/dinner) was just fried cubes of silken tofu with a little nondescript brown sauce drizzled over.

Desserts are minimalist, with a battered, fried banana ($5) and mung bean/rice cake dumpling in coconut broth ($5) earning equally indifferent responses from my companions.

On the whole, there is wonderful food to be had, but some local knowledge is needed to avoid pitfalls. It's the hit-or-miss service, though, that can be maddening. Two of my three visits were marred by young and untrained staff ignoring our table, failing to check on food, and jabbering among themselves while we sat desperately hoping for a check, in an otherwise empty dining room.

I truly like Sok Sab Bai, but I wish they'd amp up the dynamism that built their brand. It's still there, but I feel like the suit and tie they donned put a damper on their original, rowdy spirit.

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Beer, sake, and wine. Happy hour highly recommended, runs all day Monday, and Tuesday-Friday 3-6 pm. Specials listed daily on website.