Stovetop Clambake

In a saucepan, combine the potatoes with salted water to cover. Bring to a boil over high heat, then reduce the heat to medium. Simmer for 5 minutes. Drain and set aside.

Lay a double layer of cheesecloth about 15 inches square on a work surface. Discard any clams that are gaping and do not close when tapped. Arrange half of the clams on the cloth and fold to make a flat, somewhat loose bundle. Tie the ends with kitchen string. Repeat with the remaining clams and then make a third bundle with the potatoes.

In a large pot, insert a steamer rack or perforated insert that stands several inches above the bottom of the pot. Pour in water to a depth of 1 to 2 inches. Cover and bring to a boil over high heat, then turn off the heat. If using the rockweed, arrange a thin layer on the steamer rack. Set the lobsters on top, arrange the bundles of potatoes and clams on the lobsters, and then cover with another layer of rockweed. Cover, bring to a rapid boil over high heat and cook for 16 to 18 minutes. After 8 minutes, lift the lid and set the ears of corn on top. Check for doneness by using tongs to see if the clams have opened. The lobsters should be bright red and the steam should carry the sweet smell of cooked lobster.

Using the tongs, remove everything from the pot, discard the rockweed and pile the food on a large platter. Snip open the bundles and discard any clams that failed to open. Divide the butter among warmed individual ramekins. Serve immediately, along with tools for cracking the lobster shells and plenty of napkins.