Braise the leeks and fennel:

1. Heat /olive oil in a wide pan.
2. Add sliced leeks and fennel; season lightly.
3. Cook on medium heat for 3–4 minutes until they start to soften.
4. Pour in the white wine and pastis and cook until almost completely evaporated.
5. Add the vegetable stock, cover, and braise gently for 10–12 minutes until tender.
6. Add the butter just before serving to emulsify the remaining liquid.

Prepare the sauce. In a small bowl, whisk together:

• Olive oil
• Lemon juice
• Capers
• Previously cooked shallots

Taste and season lightly. This should be bright and fresh, not heavy.

Grill the Horse Mackerel:

1. Preheat grill or grill pan to high.
2. Rub with olive oil, salt, and pepper.
3. Grill for 3–4 minutes per side, depending on size, until skin is crisp and flesh is just cooked.

Assemble the dish:

1. Spoon a bed of braised leeks and fennel onto each plate.
2. Place the grilled horse mackerel
3. Drizzle lightly with the caper–olive oil sauce.
4. Serve with extra lemon wedges.