Preheat the oven to 400 degrees F (200 degrees C). Plunge the tip of a sharp knife straight down just behind the lobster's eyes to humanely kill the animal.
Place the lobster on its back and use a sharp knife to cut open the cavity. Remove the stomach and intestines, and discard. Reserve the tomalley in a small bowl. Mix the cracker crumbs with the tomalley and spoon the mixture into the body cavity. Drizzle about 2 teaspoons of butter over the top. Place the lobster in a 2 inch deep baking dish.
Bake the lobster for 30 minutes, uncovered. Set oven to Broil and cook for 3 to 5 minutes just to toast the crackers before serving. Serve with remaining melted butter.