Sicilian-style mackerel with white beans and caponata recipe

Ingredients

• rapeseed oil, for frying
• 4 fresh mackerel fillets (2 x 180g packs)
• 4 tbsp rapeseed oil
• 1 red onion, finely diced
• 3 celery sticks, finely diced
• 3 garlic cloves, finely sliced
• 1 large aubergine, cut into 1cm dice
• 1 tbsp tomato purée
• 300g passata
• 2 tbsp red wine vinegar
• 1 tbsp clear honey
• 2 bay leaves
• 50g pitted green olives, roughly chopped
• 50g sultanas
• 50g toasted pine nuts
• 1 tbsp capers
• 1 x 570g jar organic white beans (we used Bold Bean Co), drained
• a handful of chopped fresh parsley, plus extra to serve