Uninformed visitors to the new Momofuku Ssäm Bar are likely to miss the best of it. For one thing, most of them probably won’t arrive between 10:30 p.m. and 2:30 a.m., which is when the dinner menu is served. And those who get past that hurdle may be nonplussed by the restaurant’s numerous other idiosyncrasies.

Panelled in dark wood, staffed by intense, knowledgeable young men, and decorated only with a vintage John McEnroe poster, the Ssäm Bar is a hip, polished East Village den. It’s the brainchild of David Chang, chef and owner of the nearby Momofuku Noodle Bar, which is similarly driven by its chef’s penchants and tastes. The culinary aesthetic is one that stays behind the scenes at most restaurants, but is familiar to anyone who’s spent time with kitchen workers at play: a glorification of pork fat, chili heat, organ meats, staying up late, and drinking.It’s no wonder Mr. Chang’s clientele includes a lot of off-duty cooks.

During the day and through mid-evening, the restaurant makes a fairly conventional living as a cafeteria-style fast food joint, serving Asian-inflected burritos ($9) and rice bowls ($13), made to order. (The “ssäm” in the name is the Korean word for wrapped foods.) Each is an unlikely but tasty commingling of beans, spicy kimchi purée, and a choice of organic chicken, shredded Berkshire pork, or spicy hunks of tofu, and each is a substantial meal.

Come nightfall, covers go over the plastic fork dispensers, and the open kitchen to the side, which has been mysteriously empty all day, comes into its own. The nighttime menu is one of smallish plates and snacks. A couple of types of oysters are served, $3 apiece, as well as a beautiful little pink fold of vinegary cured yellowtail ($15), which comes to the table under a crunchy sprig of pea leaves.

But the pig is paramount. Steamed buns appear, filled with luxurious pork belly ($9). A quartet of soft spring rolls ($9), stuffed with charred lengths of Berkshire pork chop and wrapped with lettuce, offer lovely contrast. Even pork gets a touch of pork: Mr. Chang wraps a plump sausage ($8) in smoky bacon before grilling it and laying it with tangy kimchi on a ciabatta roll.

Where a less pig-happy restaurant might offer just one ham platter, Momofuku has four. If you don’t walk into Momofuku with informed opinions about ham, you can certainly leave with them, along with a bellyful of finest Southern pork, dressed with house-made chunky apple butter.

Heaps of smoky, fatty Tennessee bacon dice pep up a salad of roasted brussels sprout halves, kimchi, and crunchy apple slices ($12). The kimchi-laden sardine sandwich ($13) is the best sardine sandwich I’m aware of, with three big, silvery, grill-blistered fish and beautifully balanced fresh flavor. Another sandwich ($8), made with head cheese, ham, and a thin layer of chicken liver paté, is reminiscent of Vietnamese sandwiches’ contrasting bursts of flavor, but the garlicky slaw that drenches it, made with Japan’s sweet Kewpie mayonnaise, tends to overwhelm its subtlety.

Aficionados of what a waitress friend of mine calls “gross-out meats” will find plenty to enjoy: tripe, sweetbreads, veal head terrine. The tripe ($11) is found in a red and spicy Korean-style stew, its chewiness offset by tender pieces of (of course) pork. Raw onion comes on the side, so it retains its crunch up until the moment when you dump it into the stew (or perhaps just so you can admire how expertly it’s diced). Chunks of veal sweetbreads ($13) are fried to golden crispness surrounding hot, creamy middles.

The restaurant pours no still wine, just 10 or so fizzy varieties, including a popular Spanish rosé from Castell Roig ($8/$32) and the unusual plum-colored, creamy Leconfield sparkling shiraz ($60).A few sakes, OB Korean beer ($5), and Hitachino’s citrusy white and full-bodied red ales ($9) round out the beverage list. Mr. Chang also serves Dr. Pepper. Not that he needs a gimmick to set Momofuku apart; he just likes it.

Momofuku Ssäm Bar (207 Second Ave. at 13th Street, 212-254-3500).