Fresh Atlantic mackerel fillets seasoned with sea salt and cracked black pepper, grilled skin-side up under high heat until blistered and crisp, served with lemon wedges and grain mustard dressing.
Slash the mackerel skin with 3 shallow diagonal cuts. Brush both sides with rapeseed oil and season generously with sea salt and black pepper.
Preheat grill to high. Place mackerel skin-side up on a foil-lined baking sheet. Grill 7-10cm from heat source for 4-5 minutes until skin is crisp and blistered.
Carefully turn fillets over and grill for 1 more minute until the flesh is cooked through and succulent.
Serve immediately with grilled caramelized lemon halves, peppery watercress, and a drizzle of wholegrain mustard dressing.