The good news at the youngest restaurant in the impressive collection of Ashok Bajaj is that the front dining room has gotten quieter, thanks to as much as $15,000 poured into sound-proofing the place. What hasn’t changed is the uneven food coming from the Penn Quarter kitchen. At my last meal, the pork belly and the salmon entrees were almost indistinguishable from one another in their gloppy broths, and the fish dish suffered further from a “spring” vegetable ragout that smacked more of winter. A survival guide for Nopa, named for the American restaurant’s location north of Pennsylvania Avenue, could start and end with fried food. Among the snacks is cayenne-fired chicken that gets rolled in sweet rice flour and is fried twice for a crackling finish. And among the sweets are nubby fruit pies filled with a sign of the season (rhubarb most recently) and cooled down with a scoop of ice cream (strawberry on my visit). Come to think of it, the fried cod sandwich is pretty good, too, a mouthful of hot fish and hotter mustard. Oysters on the half shell make a nice launch; espresso makes a strong finish. The bar for restaurants is high in this part of the city. Nopa competes on service and style but continues to be held back by its cooks.