Grilled Mackerel with Rhubarb or Gooseberry Relish

Name: Grilled Mackerel with Rhubarb or Gooseberry Relish
Prep time: 25 min
Cook time: 10 min
Total time: 35 min
Ingredients: 200 g (7 oz) rhubarb or gooseberries, rhubarb in 1 cm dice, gooseberries topped and tailed; 40 g (3 tbsp) sugar; 2 tbsp cider vinegar; 1 small shallot, finely chopped; 1 pinch fine sea salt; 4 (about 10 oz each) whole mackerel, gutted and cleaned, about 300 g each; or 8 fillets; 1 tbsp neutral oil; 7 g (1¼ tsp) fine sea salt; freshly ground black pepper; 1 lemon, wedges; 2 tbsp chopped dill or parsley

Blistered, oily mackerel cut with a sharp, sweet-sour fruit relish

Serves: 4
Hands-on: 25 min
Total: 35 min
Level: Easy

Mackerel is cheap, sustainable and full of flavor, and it needs only fierce heat and something sharp beside it. Scoring the skin lets the heat in and the fat out, so the skin chars and blisters while the flesh stays juicy. A quick tart relish of rhubarb or gooseberries is the classic Northern European partner.

Ingredients

Relish

200 grhubarb or gooseberries (7 oz)rhubarb in 1 cm dice, gooseberries topped and tailed
40 gsugar (3 tbsp)
2 tbspcider vinegar
1small shallotfinely chopped
1 pinchfine sea salt

Fish

4whole mackerel, gutted and cleaned (about 10 oz each)about 300 g each; or 8 fillets
1 tbspneutral oil
7 gfine sea salt (1¼ tsp)
freshly ground black pepper
1lemonwedges
2 tbspchopped dill or parsley

Diet: Gluten-free, Dairy-free, Pescatarian
Allergens: fish, sulphites
Season: Spring, Summer

Method

For the relish, put the fruit, sugar, vinegar, shallot and salt in a small pan. Simmer, stirring, until the fruit has just collapsed but some pieces hold their shape, 5–7 minutes. Cool. 6 min
Heat your grill to high, or set an oven broiler (top grill) to its highest with the rack 8–10 cm from the element. For a barbecue, aim for a hot direct fire.
Pat the fish dry. Cut 3–4 diagonal slashes, 5 mm deep, into both sides of each whole fish (just the skin for fillets). Rub with oil and season inside and out with the salt and pepper.
Grill or broil until the skin is blistered and charred in spots, 4–5 minutes. Turn carefully with a wide spatula and cook the other side for 3–5 minutes (fillets need only 2–3 minutes skin side and 1 minute flesh side). 9 min
Check the thickest part by the backbone: the flesh should be opaque and lift cleanly from the bone, at 55–60°C (131–140°F). Mackerel is forgiving; its fat keeps it moist.
Serve straight away with a spoonful of relish, lemon wedges and the herbs.

Why it works

Oily fish like mackerel tolerates high, direct heat because its fat keeps the flesh moist while the skin crisps. Slashes speed heat into the thickest part so the outside doesn't burn before the center cooks. The sharp acid and sugar of the relish cuts through that richness the way a squeeze of lemon would, only more so.

Common mistakes

Buying tired fish. Mackerel spoils fast; eyes should be clear and the skin bright and stiff. Cook it the day you buy it.
Turning too soon so the skin tears. Wait until it releases.
Overpowering it with marinades. Salt, heat and acid are all it needs.

Variations

Mackerel on toast: Grill fillets, flake onto toasted rye spread with horseradish crème fraîche and top with Quick Pickles.
Japanese-style shioyaki: Salt the fillets 20 minutes ahead, broil and serve with grated daikon, soy sauce and rice.