Ceviche

It is very important that the fish is undoubtably fresh.;Boil, peel and dice the sweet potatoes. Slice the fish into strips measuring about 2 x 1/2 inch. Halve and thinly slice the shallots, quarter the tomatoes, seed and slice the red chillies, chop the coriander stems and root. Lay all the ingredients in a shallow dish, except the potatoes and the coriander leaves, and pour over the lime juice, turning the fish strips to fully coat them in the juice. Cover with clingfilm (plastic wrap) and leave for 10 min, until the fish acquires a whitish colour on the outside. Season with salt and pepper and serve on little plates or in martini glasses, decorated with the coriander leaves and garnished with the sweet potatoes, which balance the heat of the red chillies.