- 1/2 Teaspoon lemon zest
- 1 1/2 Teaspoon lemon juice
- 1/3 Cup extra-virgin olive oil
- 1/4 Cup pitted Kalamata olives, cut into slices
- 3 Tablespoons finely chopped oregano, plus 6 large sprigs
- 1 (3 ½ pounds) cleaned whole Spanish mackerel
- 2 1/2 Tablespoons vegetable oil
- 6 lemon slices
Whisk together lemon zest, juice, salt, and pepper. Pour in the olive oil in a stream, whisking until combined well. Whisk in olives and chopped oregano.
With a sharp paring knife, make 1-inch long slits at 2-inch intervals down the middle of the fish, on both sides. Brush the fish all over with vegetable oil, and season with salt and pepper. Season fish cavity with salt and pepper, and fill the cavity with 3 lemon slices and 3 oregano sprigs. Arrange remaining lemon slices and oregano sprigs on top of fish and tie fish closed with kitchen string.
Preheat grill to medium-high heat for cooking. If using a charcoal grill, open the vents on the bottom of the grill before lighting the charcoal.
Grill fish on lightly oiled grill rack, covered only if using gas grill, for 15 minutes. Turn fish over using a metal spatula and tongs, and grill for 15 more minutes, until just cooked through.
Transfer fish to a large serving platter, remove kitchen string, and pour lemon-olive sauce over the top before serving.