My waitress at the new Lily Kai's in Petaluma arrives to take my order while I'm studying the elaborate Chinese characters carved into the wall next to my table.

"They mean good luck," she says, as I run my fingers lightly over the elegant, coral-colored etchings in the golden-tan tiles. "Happiness." Then, quickly, she adds, "Do you know what you want?" The little restaurant is packed on this late weekend afternoon, and the service is polite but efficient. I do. The bistro-chic spot is a fancier offshoot of the Lily Kai's in Mill Valley, with bit of a Thai bent (mild curry lamb or spicy basil prawns, $7.95), a smattering of dim sum (fluffy barbecue pork buns, $3.25) and a few dressier plates (roast duck with steamed lotus buns, $11.95, or free-range chicken with fresh mango in ginger-garlic sauce, $9.25).

It's all very tasty-sounding fare. But I want egg rolls, my acid test for any Chinese restaurant. An egg roll is a basic thing, perhaps, but if a place gets that whisper-thin wrapper perfectly crisp, and those shredded veggie innards properly crunchy-juicy, it bodes of a kitchen paying attention to details.

I want hot and sour soup, too. The fiery white pepper and sharp vinegar base must balance, and not turn musty or metallic. It takes a careful chef to get it right. In fact, I've been known to sample just egg rolls and soup at a Chinese restaurant, and if they're not up to my expectations, leave without ordering entrées.

At Lily Kai, opened three months ago in a strip mall on the eastern edge of the city, I end up sticking around not only for the entrées, but for an extra appetizer, two side dishes and a mental note to come back again soon.

OK, so the egg rolls I get ($4.95) are actually quite ordinary. Yet I've already fallen in love with the deliciously tart soup ($5.35, small) that grows more alluring with each chicken/tofu/mushroom-stocked spoonful. A dim sum of siu mai ($5.25) absolves any egg-roll disappointments, too, the savory dumplings plump with pork and whole bay shrimp and served in a bamboo steamer basket.

A generous platter of lovely tender-meaty citrus duck ($7.95) would be just as good with half the amount of sauce, because the thick, spicy stuff packs a wallop capped by curls of bitter orange skin. I adore it, but wish for more of the crispy-skinned bird to sop it up. Instead, I fold sauce into my sides of nicely greaseless vegetarian (no egg) fried rice ($6.25) and steamed organic brown rice ($1.50).

Chow mein ($6.25) shows more sauce skill, with an intense, rich brown broth (no MSG, and not too salty, thank you) atop a crunchy-tender garden of mushrooms, zucchini, carrots, asparagus, baby bok choy, water chestnuts and broccoli. I leave Lily Kai's thinking that I need to give the egg rolls another chance. Everything else left me with a smile etched on my face. And that means "happy" in any language.

Lily Kai, 3100 Lakeville Highway, Petaluma. Open for lunch and dinner, Monday-Saturday; dinner only, Sunday. 707.782.1132.

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