I myself have never had Scandinavian mashed-potato flatbread but most of my family has (though they call it potato pancakes) and they say they're delicious.

The ingredients call for 3 cups of potatoes cooked and mashed with 2 tablespoons of milk, 1/2 teaspoon of salt, 3 tablespoons butter, 1/2 teaspoons baking powder and 1 cup flour.

When the potatoes are cool enough to handle, add the salt and butter. Mix baking powder with a small amount of flour and add to the potatoes. Add enough flour so that the dough can be rolled very thinly on a floured board. Roll only a small portion at a time. Cut into quarters and bake on a hot, ungreased griddle, browning lightly on both sides.