Potatoes, onions, and any kind of chopped or minced meat such as sausage or ham diced and then pan fried. It is often served with a fried egg, pickled beetroot slices, sour pickled gherkin slices, capers and sometimes ketchup or brown sauce.
Surströmming has been part of northern Swedish cuisine since at least the 16th century. Surströmming is often eaten with crispy bread. The two most common toppings are potatoes (either sliced or mashed, often almond potatoes) and finely diced onion.