Preparation / Directions:
In a small bowl, combine mayonnaise, lemon juice, garlic, and rosemary. Cover and refrigerate aioli until ready to use or for up to 2 days.
Rinse fish and pat dry. Brush all over with oil. Arrange fish on cooking grate. Place lid on grill.
Cook, turning once with a wide spatula halfway through cooking time, until fish is opaque but still moist in center (about 10 minutes; cut to test).
Using spatula, transfer fish to a platter or individual plates.
Serve with aioli.
Season to taste with salt.