Brendan’s is a revelation. Located on a frenetic stretch of West 35th Street, it is a serene oasis. The Irish-owned Brendan’s (yes, there is a Brendan and he’s on the scene) — which serves hearty, understandable American favorites — is a lovingly restored relic of Old New York.

It occupies a soaring space that once was a turn-of-the-20th-century hotel called the Gregorian. The present owners probed beneath the long-covered and abused interior of the old hotel and brought it back to life.

Its storefront (which looks like hundreds of others) gives no clue as to what lies within. It’s a place of intricately designed beams and pillars, high overhead archways, a magnificent marble fireplace, long and narrow stained-glass windows, massive upside-down umbrella lighting, and impressive wall decorations. There’s a wrought iron-bordered balcony and fresh flowers and candles on each of its tables.

Once past the bar room (it’s a safe distance from the dining room), with its Old New York saloon floor of tiny tiles, there’s surprising and welcome quietude, cool jazz, baskets filled with raisin-studded Irish soda bread, and a smiling, hustling bevy of Irish waitresses.

Appetizer portions are almost main course-sized and entrées are larger than that. Big desserts are also the norm and nearly all the dishes look like pictures out of Bon Appetit. Yes, there is variation in the desirability of those dishes, but all are generously portioned, handsomely presented, solid, straightforward preparations. Gobs of sour cream accompany baked potatoes, the prime rib’s terrific horseradish sauce comes not dabbed atop the meat but as a substantial and bountiful dip, and two vegetables (asparagus and broccoli) plus potatoes accompanied many entrées.

The appetizers I sampled were noteworthy. The crabcakes boasted mostly lump crab meat, not bready filler, and their remoulade sauce was put into overdrive by a discrete touch of chipolte chili, while an expansive plate of what seemed like a half-pound of Irish smoked salmon was garnished with plenty of capers, dill-kissed cream, brown bread, red onions, and a mountain of greens. Yet the numero uno starter was the crisp tiger shrimp tostado: five tender shrimp on slightly spicy pools of tomato poblano chili salsa and black-bean sauce, surrounding a tostada topped with lime-flavored frisee.

A gargantuan Irish shepherd’s pie, festooned with mashed potatoes, will appeal to those who like their beef to be finely ground rather than chunky, while chewy though tasty pork medallions were enhanced by good, full-bodied applesauce. A volcano-size portion of tangy, sesame-sprinkled Asian-marinated chicken around greens dressed with miso vinaigrette, a toss of cashews, and a nest of soba noodles is recommended, as is the crusty, blackened prime rib of beef with that wonderful horseradish sauce.

42 W. 35th St. btw. Fifth & Sixth Aves., 212-564-5405