You wouldn't think that anything as pure and simple as a bucket of vapored bivalves could be any better or worse than any other, but we've had enough dry, stringy, coppery, mean-spirited moules in drippings devoid of any fragrant succulence to deeply appreciate the ne plus ultra served at Mocca. Not only are its mussels sweet and plump, they're also served in a rich, garlicky cream sauce with the warm Mediterranean savor of fresh fennel and an undertone of Pacific seaspray. (Long spears of buttered toast are provided to sop up this revivifying elixir.) The brasserie itself is very Parisian in ambience, with bright lighting, mirrored walls, aproned waiters, and escargots aplenty. It's very nice to sit at one of the sidewalk tables, watching the world go by, Sauvignon Blanc and sweet-scented mussels at hand. Cash only.