Flame and roast an aubergine until the middle is cooked. Remove from oven, scrape out the aubergine and blend together with olive oil, smoked paprika, salt and pepper, and set aside (skin can be discarded or used in another recipe).
Coat mackerel fillet in a thin layer of flour, salt, pepper and smoked paprika, and fry in brown butter.
Toast sourdough, spread on a layer of aubergine purée, top with mackerel fillet and sprinkle with crispy fried onions and pomegranate seeds. So good!!