Moroccan-spiced mackerel with tomato and onion relish Author: Jack Catherall Serves: 2 Ingredients For the tomato and onion relish: 1 tsp fennel seeds 1 tsp cumin seeds 2 tsp ground cinnamon 1 tbsp vegetable oil 5 peeled plum tomatoes, chopped 2 medium onions, chopped 3 tbsp light brown sugar 1 tbsp black onion seeds 1