Combine 1/4 cup melted butter, lemon juice, 1/2 teaspoon salt, and 1/4 teaspoon pepper in a small mixing bowl; stir well, and set aside.
Place crabs, back side up, in a shallow baking pan; sprinkle with remaining salt and pepper. Add water and remaining 1/4 cup melted butter to pan.
Broil crabs 4 inches from heating element 3 minutes on each side or until crabs are lightly browned and crab legs are crisp.
Transfer crabs to a warm serving platter. Garnish with parsley, and serve with reserved butter sauce.