Instructions

1. Wash, scrub and pat dry the potatoes, then prick them all over with a fork. Place them on a lightly greased baking sheet. Season with salt.
2. Bake for about an hour, in a medium-hot oven, until the potatoes are cooked through (test with a skewer). Let the potatoes cool. Rest or chill them until you’re ready to serve.
3. Cut the potatoes in half (lengthwise). Using a spoon, scoop out the potato flesh, making sure the skin doesn’t tear by holding the potato half in your hand.
4. Rub some butter or oil inside the skins, then place them, skin side down, on a lightly oiled baking sheet. Bake at 170-190°C for 8-10 minutes until crispy and golden.
5. Meanwhile flake the mackerel and chop the spring onions, then add these to the scooped-out potato flesh. Add the horseradish mixture and the chopped chives. Season with salt and pepper. Add the cayenne. Mix gently, taste, and adjust the seasoning/heat.
6. Take the potato skins out of the oven, and fill them with the potato& mackerel mixture. Bake in the oven for about 10 -20 minutes to warm through.