Many New England restaurants will serve you a heavy, stew-like chowder laden with cream and thickeners. We prefer this light fish chowder. A milky broth allows the sweet flavors of the fish and potatoes to come through. Creamy but not too rich, it makes a cozy meal that soothes the soul, bowl after bowl. Only warm squares of Cakey and Sweet Cornbread can make it any more perfect. Happily, it’s a snap to make. You start by quickly poaching fish in water with some aromatic veggies. Then you set the fish aside for later so it won’t overcook. The cooking water becomes your fish stock. And the chowder stays light because the only starch…