The finished recipe. Grilled Mackerel with New Potatoes and Salsa VerdeIngredients 1 to 6. 150 g Mackerel fillet (Two fillets. Ask for them pin-boned. Weighed raw, skin on unless the method says otherwise. Cooked weight is roughly 20% less for the same fillet.). 180 g New potatoes (Raw weight, skins on.). 100 g Green beans. 8 g Anchovy fillets in oil, drained (Two fillets. They dissolve into the sauce and nobody eating it will know they are there.). 8 g Olive oil. 1 tsp, about 6 g Dijon mustardIngredients 7 to 10. 1 clove, about 3 g Garlic. A teaspoon, rinsed Capers. A large handful Fresh parsley. Juice of half a lemon Lemon juiceStep 1. Boil the potatoes for fifteen minutes, dropping the beans in for the last three, then drain.Step 2. Chop the parsley, anchovies, capers and garlic together on a board until fine, scrape into a bowl and stir in the mustard, oil and lemon.Step 3. Season the mackerel, lay it skin up on a foil-lined tray and grill on high for five to six minutes, until the skin blisters and the flesh flakes.Step 4. Halve the potatoes while warm and toss them with the beans and half the salsa verde. Set the fish on top and spoon the rest over.