Grilled Mackerel with a Sweet Soy Glaze

• 4 mackerel fillets 
• zest and juice 1 lime, plus extra wedges to serve
• 1 tbsp extra-virgin olive oil
• butter, for greasing
• steamed baby bok choi or spinach to serve

For the sauce

• 2 tbsp soy sauce
• 1 red chilli, deseeded and cut into matchsticks
• juice 1 lime
• thumb-sized piece ginger, grated
• 2 tbsp muscovado sugar
• Half a red pepper finely sliced

1. Score the mackerel fillets a couple of times on the skin, then lay them in a shallow dish ready for grilling. Sprinkle with the lime zest and juice, and leave to marinate for 5-10 mins.
2. Place all of the sauce ingredients and the red pepper and spinach in a small pan with a splash of water and gradually bring to a simmer. Cook for 5 mins to thicken slightly, cook for another  then remove from the heat and set aside.
3. Turn the grill to its highest setting and place the mackerel on a greased baking tray, skin side up. Sprinkle the fillets with the olive oil and some sea salt, then grill for 5 mins until the flesh is opaque and cooked through.
4.  lay mackerel fillets on  a plate, drizzle with the sauce and serve with a wedge of lime and rice.