Prepared in 50 minutes or less.
Place a metal steamer rack in the bottom of a 16-quart pot at least 10 inches in diameter. If using seaweed, place half of it on and under the steamer rack. Add sweet potatoes (reserving 1 for the top as a “tester”) and onions.
Stand corn along edge of pot, stem end down. Add peppers and garlic. Sprinkle with red pepper flakes, salt (if using) and rosemary. Add shrimp, tied in cheesecloth. Place clams, tied loosely in cheesecloth, over the shrimp and the “tester” sweet potato on top. Pour beer or wine over. Place a layer of seaweed and/or corn husks on the top and cover with the lid.
Place pot on a fire grate over a white-hot fire (adding more briquettes first, if necessary) or on a stove over high heat. Cook until strong gush of steam escapes (about 12 minutes on the stove, about 35 minutes on the grill).
Reduce the stove heat to medium (leave outdoor fire as is) and start timing. Steam-cook for about 15 minutes or until the “tester” potato is tender and the shrimp are bright pink. Discard seaweed and/or corn husks. Arrange shrimp and other ingredients on a large serving platter. Serve with Creole Sauce and/or Lemon Butter and lemon wedges.
Makes 4 to 6 servings.