A whole mackerel or bluefish is about 2 feet long, so you will just be able to fit it on an angle in a large rectangular gas grill or a wide oven; see cooks' notes, below. You might want to measure your grill (or oven) before choosing a fish to make sure you'll have enough room.

　　Active time: 45 min Start to finish: 1 hr

　　

Ingredients

Makes 4 servings

　　1/2 teaspoon finely grated fresh lemon zest

　　1 1/2 tablespoons fresh lemon juice

　　1/3 cup extra-virgin olive oil

　　1/4 cup pitted Kalamata olives (1 1/4 oz), cut into slivers

　　3 tablespoons finely chopped fresh oregano plus 6 large sprigs

　　1 (3 1/4- to 3 1/2-lb) cleaned whole Spanish mackerel or bluefish (with head and tail)

　　2 tablespoons vegetable oil

　　6 (1/4-inch-thick) lemon slices

　　

Special Equipment

a 22-inch grill; kitchen string

　　

Step 1

Whisk together zest, lemon juice, and salt and pepper to taste, then add olive oil in a stream, whisking until combined well. Whisk in olives and chopped oregano.

　　

Step 2

Make 1-inch-long slits at 2-inch intervals down middle of fish on both sides with a sharp paring knife, then brush fish all over with vegetable oil and season with salt and pepper. Season fish cavity with salt and pepper, then evenly distribute 3 lemon rounds and 3 oregano sprigs in cavity. Close cavity, then evenly arrange remaining 3 lemon rounds and 3 oregano sprigs on top of fish and tie fish closed with string at 2-inch intervals, securing lemon slices and oregano sprigs to fish.

　　

Step 3

Prepare grill for cooking. If using a charcoal grill, open vents on bottom of grill, then light charcoal. Charcoal fire is medium-hot when you can hold your hand 5 inches above rack for 3 to 4 seconds. If using a gas grill, preheat burners on high, covered, 10 minutes, then reduce heat to moderate.

　　

Step 4

Grill fish on lightly oiled grill rack, covered only if using gas grill, 15 minutes. Turn fish over using a metal spatula and tongs, then grill until just cooked through, about 15 minutes more.

　　

Step 5

Transfer fish to a large platter using 2 metal spatulas, then cut and discard string. Serve fish with sauce.

　　Cooks' notes:

　　• If you aren't able to grill outdoors, whole fish can be roasted on an oiled large baking sheet (17 by 14 inches) in middle of a preheated 425°F oven, without turning, until just cooked through, 30 to 35 minutes. If fish extends beyond baking sheet, fold up two 12-inch-long pieces of foil and put under head and tail to extend baking surface. • If fish tail begins to brown too much (on grill or in oven), loosely wrap with a small sheet of foil.