Cover and let sit overnight.
In the morning, divide the dough into balls of 50 grams each and let them rest, covered for 10 minutes.
Then roll them into very thin circles on a well floured board. Prick well with a fork or roll with a Swedish rolling pin made to poke indentations in crackerbread.
Cut a hole in the centre with a cookie cutter.
Place on a baking tray that is covered with polenta. Spray with water and top with the seeds and/or salt of your choice.
Bake at 225 degrees C for 8-10 minutes. they should be completely crispy when they come out of the oven.
Cool on a wire rack. If they are not totally crispy, you can put them back in a warm oven and then turn the heat off.
Let them stay in there overnight and they will be crispy in the morning. String them up or store them in an airtight tin.
Eat with herring, boiled potatoes, sourcream and chives, beer, acquavit and plenty of rousing Swedish songs. Or just any time.