Stove Top: To cook four 8-ounce tails, bring 6 cups salted water to boiling in a 3-quart saucepan. Add the defrosted lobster tails. Simmer, uncovered, for 8 to 12 minutes or until shells turn bright red and the meat is tender when poked with a fork. Conventional Oven: Defrost lobster tails. When the lobster tails are defrosted, insert point of kitchen shears between the meat and the hard shell. Cut the shell down the center of the back with scissors, leaving tail fan intact. Lift uncooked tail through the slit to rest on the top of the shell (this is called a piggyback lobster tail.) Preheat oven to 350 degrees. Place prepared lobster tails on a baking sheet, brush each lobster tail with melted butter, and bake approximately 15 minutes or until an internal temperature of 140 to 145 degrees. Do not overcook, as the lobster will become tough and rubbery. While cooking, lobster shells will turn their characteristic bright red color well before the meat is thoroughly cooked inside. Serve immediately. Grill: Grill lobsters cut side down over medium high heat about 5 minutes, until the shells are bright in color. Turn the tails over and spoon a generous tablespoon of butter onto the butterflied meat. Grill for another 4 minutes, or until the lobster meat is an opaque white color.