Cut the tomatoes into quarters and liquidise. Pass the pulp through a sieve with the back of a spoon to filter out the broken seeds and skin. Really push through every last drop
Rub the mackerel fillets with a little olive oil on their skin side and cut them as instructed. Heat a large non stick sauce pan on a medium high heat and fry the mackerel fillets, they should immediately sizzle on entering the pan. Fry them until there is one fingers width of pink meat down the middle of each piece, approx 2 minutes. Remove the mackerel pieces to a plate. There should be a fair amount of fish fat in the pan. Drop in the coriander seeds with the garlic, chile and thyme then stir for a minute or so to soften. Regulate the heat so as not burn the garlic or fat. Add the carrots and the tomato pulp to the pan with the water wine and orange juice, salt and pepper. Simmer very gently for 15 minutes, adding the courgette for the last 4 minutes, until the carrot as softened and the liquid reduced a little. Lower in the mackerel pieces carefully and pour in any juices that leaked onto the plate. Cook the fish for a further 2 minutes in the soup base. Serve with a scattering of dill on top.