Pat dry and fillet the mackerel – make sure to remove the pin bones.
Slice the mackerel and put 2 pieces of cheddar cheese strips into each mackerel fillet incision.
In a bowl, gently whisk together the 2 eggs. Add the gratedhorseradish, grated cheese, salt and pepper to taste, then mix.
Heat oil in a frying pan. Dip each mackerel fillet into the egg mixture and gently lower the fillet into the oil.
Cook the mackerel fillet for approximately 6-7 minutes each side, in a frying pan, skin side first and then the flesh side.
Add the diced tomatoes and the rocket at the centre of the plate.
Once the mackerel fillets are cooked to your liking, placed the fillets on top of the plate and serve.
Serving Suggestions: Serve on the warmed platter and garnish with parsley. Sprinkle over some grated cheese and serve with oven-baked potatoes.