Prepare the lobster for splitting either by inserting a sharp knife in its back between the body and tail shells to sever the spinal cord, or plunge it into boiling water for about 5 min. and then remove.
(If you are sure of your market, the dealer will undoubtedly split them for you.) Next, cross the large claws and with a sharp-pointed knife begin at the mouth, make a deep incision, and cut quickly through the body and the entire length of the tail.
Lay open the lobster as far as possible and remove the stomach and intestinal canal.
Crack the large claws.
Brush the meat with melted butter, season with salt and pepper and arrange the lobster in a baking pan, shell side down.
Bake in a moderate oven of 375° F. for 30 to 40 min., depending upon its size.