Step 1

Heat 1 1/2 tablespoons of the oil in a deep frypan. Add onion and 1 heaped teaspoon of salt, and cook over medium heat for 1-2 minutes, stirring occasionally, until onions start to soften but don't brown.

Step 2

Add 1/2 cup (125ml) water and the sugar, cover and cook for 15 minutes until onions are very soft. Remove lid and cook until onions start to brown and caramelise, then add rosemary, sultanas, tomatoes and lemon zest and juice, and continue to cook for 3-4 minutes until quite thick. Season to taste, stir in parsley and set aside.

Step 3

Heat a chargrill or frypan over high heat. Season the fish with 1 tablespoon olive oil, salt and pepper and cook for 2-3 minutes each side until just cooked through. Serve with the agrodolce sauce and wild rocket.