Just like every other holiday we eat herring. Usually with boiled, oftened coloured eggs, dark rye bread, strong hard cheeses and some smoked or cured salmon. I usually make a matjes cheesecake, and Janssons temptation (potato and anchovies bake) is common too. This food is usually consumed on Easter Eve, the Saturday, and the roast lamb is more common on Easter Day (the SUnday).
A very popular Easter cake is the Oscar II cake, named after a Swedish king. The reason it is so popular during Easter is probably because of its yellow colour and nothing else.
Note: The image is from here.