By Melanie Barnard | Before even beginning a commentary on the food, it is important here to note the ambiance of Post 154. This very visible, highly anticipated conversion of Westport’s historic, nearly 80-year-old post office, from a grand salon of its era to a youthful, dining hot spot for a generation that likely never enters a real post office at all. The place is fabulous. Original murals still adorn the walls, the imposing old clock is still the centerpiece of the room and the soaring interior columns remain untouched.

But now the ceiling is exposed in contemporary industrial style, floors are old wood and there is seating for more than 250, including an impressive but warm and welcoming bar.

Service is a similar combination of Old World correctness, and today’s offbeat casual — sometimes translating to a tad slow, but always smiling and genuine.

The food at Post 154, however, is most definitely not old-fashioned or stuffy elegant. The chef’s background and the owner’s vision bring a Latin flair to all sorts of contemporary American favorites, from a terrific burger embellished with Krystal Caves cheddar, crispy pork belly, avocado and enchilada sauce, to a memorable lobster quesadilla with classic huitlacoche (corn fungus — try it, you will like it), Chihuahua cheese, avocado and ultra-fresh salsa.

As is often the case these days, the small plates overshadow the big ones in imagination and presentation. Our favorite from this list is the eggplant “meatball” Parmesan. The tender, crunchy-edged globes of eggplant, breading and cheese are served in a truffle and herb tomato “gravy.” I’d come back for these alone. But a big bowl of perfectly cooked, sweet mussels in a saffron wine broth augmented with bits of chorizo, shallots and roasted garlic would also be a big return draw. Crab “tater tots” would be loved by kids of all ages, but the 10 little crab cakes got a bit overwhelmed by the breading, though the remoulade sauce was first-rate. Other options include St. Louis-style ribs, tuna tartar with wasabi, soy, avocado and yucca chips, as well as duck confit taquitos.

Soups and sides are winners, especially a tasso and leek chowder and corn bisque, as well as a wonderfully rich macaroni and cheese, or garlic and shallot mashed potatoes. A soup and one of the heaping salads, especially the spinach with artichoke escabeche, Belgian endive, truffle cheese and currants combine for a satisfying meal.

Among the nicely portioned main courses, we found the ultra-tender, golden chicken absolutely smothered in mushrooms most appealing, though the risotto was more like creamed rice. Halibut with roasted garlic and creamed celery with Creole shrimp “fondue” needed a bit more crunch and a tad less salt. Rosemary accented, fork-tender short ribs are rich and rewarding, especially with a texture contrast of crisped, golden shallots.

Our favorite among the desserts is the golden, light-as-air puff pastry empanadas and the dense, fudgy flan. Tres leche cake is too sweet, even for this traditionally sweet genre.

Post 154 serves up a lot of winning and imaginative dishes in a terrific venue. Go, even if for drinks and snacks.