Preparation / Directions:
Prepare the grill. Spray the grill rack with nonstick cooking spray.
In a small bowl, stir together the mustard, lemon juice, oil, Parmesan, basil, salt, and pepper. Place the swordfish steaks on the grill and brush them lightly with some of the basil basting sauce. Grill the steaks 4 inches from the heat until opaque on top, 3 to 4 minutes.
Meanwhile, add the chopped tomato and the parsley to the remaining basting sauce.
Turn the swordfish steaks and spoon the tomato-basil basting sauce over them. Grill until the fish is lightly colored, firm to the touch, and just flakes when tested with a fork, 3 to 4 minutes.
Arrange the sliced tomatoes on a platter and top them with the grilled swordfish steaks. Spoon any remaining sauce over the steaks and serve immediately.