Clams with Dijon Broth

Mustard. Clams. Two things I love, but I hadn’t tried together before. And so I was delighted with a bowl full of tiny cockles I had at Au Passage; the mustard rounds out in the clam juice to make a rich, slightly mysterious broth. Cockles are hard-shelled clams, about the size of a thumbprint. With pronounced ridges, they are very attractive but awfully hard to find on the American market, so I make my version with Manila clams instead. As with all brothy shellfish, be ready with bread to