Step 1

Light the grill or heat the broiler. In a small glass or stainless-steel bowl, mash the capers with a fork. Stir in the lemon juice, parsley, 1/2 teaspoon of the salt, and 1/4 teaspoon of the pepper and then 6 tablespoons of the oil.

Step 2

Coat the tuna with the remaining 2 tablespoons oil. Sprinkle with the remaining 1/4 teaspoon each salt and pepper. Grill or broil the tuna for 4 minutes. Turn and cook until done to your taste, 3 to 4 minutes longer for medium rare. Serve the tuna topped with the sauce.