For this recipe it necessary to have very fresh mackerel, which is easily obtained from a local fishmonger. However, if you can’t get your hands on this then salmon or smoked mackerel would work just as well. To make the ceviche more of a meal serve with a side salad and crispbreads.
Put the mackerel on a tray, skin side down and sprinkle with sea salt and 1 tsp of sugar and put in the fridge for 20 mins. Meanwhile, slice the celery into thin pieces and set aside. Mix together the Apple Vinegar and Verdemanda with a few pinches of salt and the remaining sugar.
Remove the mackerel from the fridge and pat dry with kitchen paper or a clean tea towel. Using a sharp knife, cut the mackerel into thin slices and place in a bowl.
Quarter the apple and remove the core, then cut into thin horizontal slices. Add the apple to the bowl, along with the celery and the dressing and mix well to combine. Divide between plates in a thin layer before sprinkling with chilli and grating the fresh horseradish on top.