Pickeled herring can also be used in place of mackerel; either way, this dish is an explosion of flavor, and a good example of Sweden on a plate.
This recipe is courtesy of SwedishFood.com.
Mix the salt and water for the brining solution, but there is no need to heat it. After picking over the filets to check that there are no big bones left in them (small bones will dissolve in the vinegar), place the filets in the solution for 3 hours, or until the fish is firm.
Place all the pickling ingredients in a pan and bring to the boil. Simmer for 15 minutes. Let cool.
Put the fish filets and the pickling vegetables in a sterilised glass jar or container. Pour the pickling solution into the jar until all the fish is covered. Prod the fish lightly to release any trapped air. Cover with a lid and refrigerate for at least two days, preferably longer.
Mix together all ingredients thoroughly.
Place 3 or 4 slices of beetroot on each plate. Mix the salad with the dressing, add pickled carrots, and place on top of the beetroot slices.
Roll the mackerel up with some pickled onion in the centre and sit on top of the salad. Top with some tiny dill sprigs.
Drizzle with some balsamic glaze and a little olive oil.