Grilled Spanish Mackerel with Green Sauce

Green Sauce: (makes about 1 cup)

• 2 cups loosely packed flat-leaf parsley leaves
• 1 cup loosely packed mixed tender herb leaves, such as dill, tarragon, chives, lemon balm, basil, spearmint, chervil, and/or fennel fronds 
• 2 scallions, white and green parts minced
• 2 oil-packed anchovy fillets, finely chopped
• 1 tablespoon brined capers, finely chopped
• 1 hard-boiled egg yolk , finely grated
• 1⁄4 teaspoon kosher salt
• Freshly ground black pepper to taste
• Chile flakes to taste
• 1⁄2 cup extra virgin olive oil, plus more as needed
• Grated zest and juice of 1⁄2 lemon

Grilled Spanish Mackerel:

• Four 8-ounce, skin-on Spanish mackerel fillets
• Kosher salt 
• Freshly ground black pepper 
• Finely ground dried red chiles, such as chile de arbol 
• Extra virgin olive oil 

Make the green sauce: chop the parsley and tender herb leaves, very finely. Put them in a small bowl and add the minced scallions, anchovies, capers, egg yolk, salt, pepper, and chile flakes. Mix well, and slowly drizzle in the oil, stirring to emulsify. Add the lemon zest and juice. If the sauce seems too thick, add a touch more oil. Adjust the seasoning if needed.
 
Grill the fish: prepare a fire in a charcoal grill. Season both sides of each fish fillet generously with salt, pepper, and dried chiles. Drizzle both sides of the fish with a little olive oil.

When the grill is very hot but the flames have died down and the coals are completely covered with ash, put the mackerel, skin-side down, on the grill. Allow the fish to cook for at least 2 minutes before moving it. In the meantime, watch for flare-ups, extinguishing them with a little water from a squirt bottle (beer works, too). After about 4 to 6 minutes, when the skin is crispy and a deep golden-brown, gently flip the fillets with a spatula and allow them to cook undisturbed. Grill the fish fillets for 2 to 3 minutes, until they are just cooked through. Serve with the green sauce.