“Bistros are all about the Bs,” a restaurateur once told me. “The bar, the buzz and the braise.” You don’t walk inside expecting elaborate cuisine or exorbitantly priced entrees. You anticipate a good glass of wine, a warm welcome and the kind of comforting, familiar dishes that deliver flavor and satisfaction.

Isa, a modest-sized bistro that opened in Bayside last March, delivers all of these in a beautifully renovated historic space that nods to tradition (check out the black-and-white tiled floor and the original tin ceiling) but at the same time feels bright and contemporary and fuss-free. And if the food is occasionally good instead of great, the charm of the place and the genuinely friendly staff more than make up for it.

“We wanted to create a neighborhood spot that serves the type of food we like to eat at home, or share with friends at a dinner party,” says Suzie St. Pierre, who opened the restaurant in March with her chef husband, Isaul Perez. “Isaul wasn’t classically trained, and he didn’t go to culinary school,” she says. “The menu reflects his experience working in French and Italian restaurants in New York, plus his own subtle Mexican twist on things.”

Take the lobster tostada ($10), Perez’ stand-in for a perennial New England favorite. “Everyone does lobster rolls in Maine,” his wife says. “We decided it was time to try something different.” The appetizer spotlights chunks of steamed lobster quickly sautéed in butter, then layered onto a tortilla (from La Bodega Latina) along with paper-thin shavings of fennel, a few kernels of corn and a spoonful of creamy aioli spiced with guajillo chilies. First, you taste abundant richness and spice, thanks to the generous serving of shellfish and that piquant aioli. Then you discover the morsel of softened fennel, whose subtle sweetness pairs beautifully with the buttered lobster. Next, the plump, barely cooked kernels of corn pop against your teeth, tasting of summer. The play of flavors and textures is hypnotic. One tostada made a satisfying appetizer. Three would make an unforgettable meal.

That tostada is a hard act to follow, but meatballs in marinara sauce ($8) are a reasonable runner-up. Baked instead of fried, the trio of small meatballs is served beneath an enthusiastic grating of salty Pecorino cheese. By themselves, those meatballs would be fairly bland, but dunked into a pool of bright tomato sauce and topped with all that cheese, they’re moist and pleasing. The house-made marinara is good enough that you won’t want to let it get away. Sop it up with a chewy slice of Standard Baking Co. bread or ask the attentive waiter for a spoon.

As you’d hope from a bistro chef, Isaul Perez takes braising seriously. That’s obvious the moment you tuck into a bowl of his braised lamb and creamy polenta ($20). Meltingly tender and flavorful, the lamb (from North Star Sheep Farm in Windham), tastes as if it’s been simmering for days. (“Really just one day,” his wife says. “We braise it overnight with red wine and carrots and onions and celery.”) A chiffonade of young Brussels sprouts on top of the lamb adds a streak of color and an unexpected, peppery bite. But it’s the silken consistency and flavor of the jus that tops the polenta that will open your eyes. “So that’s what comfort tastes like,” a friend murmured after trying a bite.

Unfortunately, the restaurant’s grilled pork chop ($22), served with cannellini beans and mustard greens, missed the mark. The night we visited, the greens were pungent and pleasantly bitter, but the chop was overcooked and the beans undercooked, grainy instead of creamy. Green lentils, offered as a side dish ($6) with grilled kale and butter, were also a letdown. Though these greens, too, were nicely prepared (and wonderfully smoky), the lentils lacked salt or much flavor. If you feel like a side dish, try the house cut French fries ($5). A bistro standard, they’re served with the same spiced aioli that comes with the tostada.

Isa offers a small dessert menu, with four or five choices most evenings. Tres leches cake ($6), a Mexican favorite made with condensed milk, evaporated milk and heavy cream, is comforting – moist and sweet with a consistency closer to pudding than cake. “Was this one of Isaul’s family recipes?” I asked his wife. “You’d think so,” she answered with a laugh, “but it’s mine…My husband isn’t much of a baker.” “Leave it to the girl from Pennsylvania to come up with our signature tres leches,” she said. Heritage notwithstanding, St. Pierre’s version is good. Each forkful melts quickly on the tongue, and tiny curls of candied orange peel on top provides a crunchy contrast.

Pumpkin mousse ($7) is also tasty, and one of several gluten-free dishes on the menu. (The restaurant is notably sensitive to customers with dietary restrictions; before taking orders the servers ask about allergies and restrictions.) A dollop of whipped mascarpone with the mousse tastes refreshing, but it’s the scattering of pepita brittle that challenges your molars and your expectations: It’s crunchy and sweet and surprisingly salty. An extra layer of brittle is hidden at the bottom of the dish – the topsy-turvy version of icing on the cake.

The atmosphere and the service at Isa are decidedly relaxed and informal. Based on the number of friends who seem to be meeting up after work, it’s already become a popular place for a drink. And with modest-sized portions that are reasonably priced, it’s also a fine choice for a laid-back supper. So start at the bar. Bask in the buzz. And savor the braise. This is a bistro that works.

James H. Schwartz has covered food, travel and architecture for The Washington Post, Downeast, Coastal Living and Southern Living magazines for more than 30 years. Long a commuter between Portland and Washington, D.C., he retired from his job as vice president at the National Trust for Historic Preservation in 2013 and relocated to Maine.