When ambitious chefs are ready to expand, one of the best-marked paths leads to the casual offshoot, a restaurant more downscale and accessible than the flagship that made their name.

This initially seemed to explain Balise, from chef Justin Devillier and Mia Freiberger-Devillier, of La Petite Grocery, and this darkly handsome new CBD spot looks the part.

But just past the burger and the cone of fries, somewhere between a sculptural salad of crabmeat and a hazelnut-studded lamb ragu under ruby-rare lamb loin, a bigger picture for Balise comes into focus.

This is a 21st century tavern, one that answers the growing expectation that high-aiming, compulsively interesting cuisine should be available on more casual terms and that, provided we’re ready to pay, it can fill the role of bar snack just as readily as dinner course.

The husband-and-wife team opened Balise in January in the old Ditcharo’s, a building that dates to the 1830s. That vintage is more evident after their renovation, which carries across a succession of small rooms with a mix of seafaring prints and contemporary art for a Melville-goes-modern look.

The long bar up front feels like the center of the action; the rear dining room is a little cramped between the kitchen door and service traffic; the second-floor dining room is more elegant and feels like a private club with its own bar and egress to the balcony.

Balise can serve as a gastropub, especially at lunch if you get the juice-gushing roasted pork sandwich ($14) with bitter rapini and gooey fontina; or if you just drop in for a beer and some pan-fried shisito peppers ($8), which are mostly sweet but provide the occasional, unpredictable flash of heat. Grilled asparagus ($10) with a clutch of delicately fried oysters follow suit, as does rigatoni ($14) in a beef cheek sauce that tastes like gravy and cream cooked together.

From here though, Balise gets into dishes that are highly conceptual, intricate and sometimes downright modernist.

One dubbed simply “Gulf shrimp” ($14) is arrayed across the plate with sea urchin, tiny clams, saffron aioli and fennel, as if a bouillabaisse were prepared as a tasting platter rather than a stew. There’s raw tuna ($16) presented like steak tartare with egg yolk, capers and sharp mustard all lassoed into place by pickled ramps.

Drum ($25) is fried in a caramel-colored batter but also carries the flavor of the grill from charred shafts of romaine. And that lamb ($28) mentioned above is a small, tightly composed entrée, with deep earthy and umami flavors dueling between trim slices of herbaceous meat.

Beautiful presentations and careful application of strong flavors are hallmarks here, though some dishes are too restrained and too composed. The chicken ($26), for instance, hints at the lushness of a country-style roasted bird but can’t get there with just a boneless breast in play. Know too that portions are generally small; the menu is designed for sampling various dishes, rather than getting stuffed from one.

Desserts are downplayed, with a small menu of classics with a few tweaks. Cocktails tend toward the dark and complex. The wine list is excellent, with great variety across types and prices.

The ideal first run at Balise is from a bar seat by the garde manger, a prep area for cold dishes built right into the long marble slab. Here you can watch staff apply tangy sauce Gribiche over bunches of long-stemmed broccoli or assemble salads of ribbon-thin carrots with egg, fresh tarragon and fried brioche. Delicate, boldly flavored, simple and satisfying, these chilled delicacies will only grow more appealing as the hot summer lengthens.

There’s a TV over the bar, but its placement is so subtle and its use so limited, I didn’t notice it during four visits. It may become a more obvious element at Balise once football resumes, but then football season changes a lot of things, especially in downtown New Orleans.

Balise was built for a looser approach, to be accessible at different levels and for experimentation across its menu. The place is just getting started, and it will be fun to see it roll with the varied appetites the busy New Orleans calendar brings to its door.

Follow Ian McNulty on Twitter, @IanMcNultyNOLA.