Rosemary Blue Marlin With Roasted Corn & Tomato Relish

3/4 cup extra virgin olive oil, divided
2 cups cherry tomatoes, halved
2 sprigs of rosemary, leaves stripped & finely chopped
2 ears of corn, kernels cut from cob (or 1 can whole kernel corn, drained & rinsed)
2 cloves garlic, minced
2 pounds Blue Marlin Steaks
2 teaspoons kosher salt, or to taste
1 large onion, minced
salt & pepper to taste

-To make the marinade, place 1/2 cup olive oil & 1/2 the rosemary in a resealable plastic bag. Add the Marlin, seal the bag, & turn gently to evenly coat the fish. Refrigerate for 1 hour
-Preheat the oven to 450 degrees F
-Pour 1/4 cup olive oil into an oven safe pan. Stir in the onion, cherry tomatoes, corn kernels, garlic, remainder of rosemary, & kosher salt
-Put the vegetables in the oven & cook until they are soft, about 20-30 minutes
-Preheat the grill for high heat & lightly oil the grate
-Place the fish on the preheated grill and season with salt & pepper to taste. Cook, turning once, until the fish is opaque and flakes easily with a fork-about 5 minutes each side depending on thickness
-Place the fish on a serving platter and top with the corn & tomato relish
Serves 3