ingredients

• 1 tablespoon plus 1 teaspoon unsalted butter
• 1 tablespoon extra-virgin olive oil
• 1 large leek, white and tender green part only, finely diced
• 1 celery rib, peeled and finely diced
• 1 garlic clove, minced
• 4 plum tomatoes, coarsely chopped
• 1 teaspoon finely grated lemon zest
• 1 tablespoon thyme leaves
• 1 tablespoon chopped flat-leaf parsley
• 2 ears of corn, shucked, each cut crosswise into 4 rounds
• 16 small new potatoes, scrubbed
• 3 cups fish or shrimp stock or 1 1/2 cups bottled clam juice mixed with 1 1/2 cups water
• 1 cup tomato juice
• 1/2 tablespoon Old Bay seasoning
• 1 1/2 pounds large shrimp, shelled and deveined
• 3/4 pound andouille sausage, cut on the diagonal into 1/2-inch rounds
• 1 small lemon, thinly sliced
• Salt and freshly ground pepper
• 1/2 bunch of watercress, large stems removed
• 4 thick slices of grilled country bread, for serving