Grilled Mackerel with Caramelized Onion and Lemon

Instructions

1. 1

   Begin caramelizing the onions by heating 3 tablespoons of olive oil in a large skillet over medium heat. Add the sliced onions and a pinch of salt, stirring occasionally for 15-18 minutes until they turn golden brown and sweet.

   Tip: Don't rush this step; low heat creates better caramelization and deeper flavor.

2. 2

   While onions cook, pat the mackerel fillets dry with paper towels and season both sides generously with sea salt and black pepper.

   Tip: Dry fish grills better and develops a crispier skin.

3. 3

   Preheat your grill to medium-high heat and lightly oil the grates to prevent sticking.

   Tip: If using a grill pan, heat it on the stovetop until just smoking.

4. 4

   Once onions are caramelized, stir in the minced garlic and balsamic vinegar, cooking for another minute until fragrant. Remove from heat and set aside.

   Tip: The acidity of the vinegar balances the sweetness of the onions perfectly.

5. 5

   Place mackerel fillets skin-side down on the hot grill and cook for 5-6 minutes without moving them, allowing the skin to crisp.

   Tip: Resist the urge to flip early; this creates a beautiful crust.

6. 6

   Carefully flip the fillets and grill for another 3-4 minutes until the flesh is opaque and cooked through. Place a lemon slice and thyme sprig on top of each fillet during the last minute.

   Tip: The fish is done when it flakes easily with a fork and the internal temperature reaches 63°C.

7. 7

   Transfer grilled mackerel to serving plates and generously top each fillet with the caramelized onion mixture.

   Tip: Keep the warm onions on top to maintain the mackerel's heat.

8. 8

   Drizzle with the remaining 2 tablespoons of olive oil and fresh lemon juice, then garnish with chopped parsley and additional thyme. Serve immediately.

   Tip: The bright lemon juice cuts through the richness of both the fish and onions beautifully.