Mussel ecstasy reigns at this warm Belgian bistro, with diners endlessly spooning tastes of their steamed mussels into their companions' mouths like priests giving communion. The reaction is always the same -- thoughtful mastication followed by an energetic nod of delight. Once your own black mussel pot arrives, the real fun starts. Under the fragrant fog sit two dozen of the black-shelled devils, awash in a broth of wine, salt, pepper, celery and onions. Inhale deeply and you'll be transported to the coast of Maine, Washington or Canada, where the cafe buys the mollusks. The flesh is at once soft and chewy, yielding the saltwater-and-sand taste of the shoals. Served with delicious french fries and homemade bread perfect for dipping, the moules frites are worth every cent of the $13.95. Wonderful with a glass of chardonnay.: