4 tuna steaks (about 4 oz each) 1 inch thick

Marinade:
½ c olive oil
4 T red wine vinegar
4 T chopped fresh rosemary
2 T minced garlic
½ tsp coarsely ground black pepper
¼ tsp salt, or to taste

Vegetables:
8 small red-skinned new potatoes, washed well
8 firm fresh plum tomatoes

Garnish:
½ c black nicoise olives
4 T chopped flat-leaf parsley

Preheat oven to 350 F

Mix marinade ingredients in a bowl. Place tuna steaks in shallow glass dish, coat with ½ of marinade. Refrigerate, covered for at least 1 hour, turning twice.

Prick potatoes with a fork. Bake in oven for 45 minutes or until just tender. While potatoes bake and tuna marinates, cut tomatoes in half lengthwise. Place in a bowl and toss with the remaining marinade. Add baked potatoes; marinate at least 15 minutes more.

Thread long wooden skewers (which have been soaked in water) with marinated tomatoes and potatoes, alternating the vegetables.

Grease grill with cooking spray. Remove tuna from marinade, scraping most of the bits that cling as desired; place in center of grill over medium hot coals, with skewered vegetables alongside. Grill no more than 10 minutes total, turning tuna and vegetables once during cooking. Fish should be slightly pink inside. If overcooked, tuna will be tough.

Arrange fish and vegetables on a platter. Sprinkle with olives and parsley.