Preparation / Directions:
Core the tomatoes and cut them into thick slices. Brush both sides of the slices with oil and season generously with pepper.
Heat a large cast-iron or heavy-bottomed skillet over high heat until hot. Lay the tomato slices in the pan in one layer and cook for 2 to 3 minutes on each side to char. Lift the tomato slices from the pan and set aside on a plate. Repeat the procedure until all the slices have been charred.
Put the onion slices in the same pan and cook over high heat for 2 to 3 minutes, stirring, until the onions begin to brown. Add the chopped basil and keep warm. Season the swordfish steaks with a little salt and pepper. Brush both sides of each with the remaining oil.
Heat the same or another large cast-iron or heavy-bottomed skillet over high heat until hot. Alternately, prepare a charcoal, wood, or gas grill or preheat a broiler. Cook the swordfish for 3 to 4 minutes to a side for medium. Do not overcook. Put a swordfish steak in the center of each plate and spoon the warm tomato vinaigrette over it. Sprinkle with parsley.