How to Make It
Place lobsters in freezer 60 minutes before cooking. Add 1 to 2 inches water and 3 tablespoons shrimp-and-crab boil seasoning in the bottom of a 16- to 20-quart stockpot. Add steamer basket with legs that raise basket about 1 to 2 inches above bottom of pot, and bring water to a boil over medium-high heat.
Place potatoes, onions, garlic, and sausage in basket; cover and steam 5 to 6 minutes.
Place lobsters on top of potatoes; cover and steam 10 minutes. Place clams and mussels on lobsters. Cover and steam 5 minutes. Place corn and shrimp on shellfish; cover and steam 3 to 5 minutes or until shrimp are pink and shellfish open. (Discard any that do not.)
Remove ingredients from pot with tongs and a small colander, and place on a serving platter. Serve with melted butter, lemon wedges, French bread, and additional shrimp-and-crab boil seasoning. Garnish, if desired.