Preheat the oven to 200 ° C. Wash the potatoes thoroughly and dry them. Do not peel.
Using a brush or a paper towel, rub the potatoes with rapeseed oil. Season with salt and pepper.
Put the potatoes in the baking dish and bake for 45-60 minutes (depending on the size of the potatoes) until the potatoes are browned.
Take the potatoes out of the oven. Halve the potatoes and scoop out the center (we will not need it). Put mackerel paste in the center and put it back on for about 5 minutes.