Zarandeado Grilled Fish Tacos (Tacos de Pescado Zarandeado)

Marinate the fish. In a dry skillet over medium heat, roast the unpeeled garlic, turning regularly, until blackened in spots and soft, 10 to 15 minutes. Cool, then peel off the papery skins. In a food processor or blender, combine the garlic, olive oil and 1 teaspoon table salt, and process to coarse puree. Lay out the fish on a baking sheet or pan, skin-side down. Every couple of inches make ½-inch-deep slashes crosswise in the fish to allow flavorings to penetrate and ensure even cooking. Sprinkle with salt (both sides, even down in the slashes), then scoop out half of the garlic mixture and spread it evenly over the top, bottom and sides of the fish.

To the blender or processor, add the mayonnaise, optional mustard, soy, hot sauce, lime juice, and black pepper. Spread the marinade evenly over all sides of the fish.

Grill and serve. Turn on a gas grill to medium-high or light a wood or charcoal fire and let it burn until you have a hot bed of coals covered with white ash. When quite hot, heat the basket over the fire for a few minutes. Brush or spray the basket generously with oil. Spray or lightly brush the fish with oil, then lay the oiled-side down on the basket; spray or brush the other side. Close the basket and lay over the fire with the fish skin-side down. Cook, turning every 2 or 3 minutes, until the fish is cooked through but still juicy—an inch-thick fillet typically takes 8 to 10 minutes. Gently and carefully open the basket and remove the fish to a platter. Sprinkle with salt, then serve with warm tortillas, red onion, lime and extra hot sauce for making very tasty tacos.