Peel and Cook potatoes in boiling water till done; mash with a potato masher or electric mixer, till smooth.
Measure out two cups of the mashed potato and set whatever you have left over aside (we will only be using 2 cups of potato for this recipe, you can season the left over mashed potato and have it for dinner! ).
Combine mashed potatoes, milk, salt, sugar, and butter to it, then then mash together again until it's all blended.
Put your finished mashed potatoes into a sealed container and chill in the fridge till cold (about 2 hours); The mashed potatoes must be cold and then will be slightly stiff.
Measure out your 1 1/2 cups flour; add 1/2 cup of that flour to the mashed potatoes and stir to try to incorporate.
Again, from that 2 cups, sprinkle flour on a flat surface to keep the lefse dough from sticking to the counter; Put the chunk of mashed, floured potatoes down into the middle of the floured area; Knead it for about ten minutes, gradually incorporating another half cup of flour; After it has a whole cup of flour in it, it will feel much doughier and nothing like mashed potatoes anymore.
Seperate dough into 8 equal pieces, and roll each piece into a ball.
Spread more flour out onto your surface - the best way to avoid sticking is to flip the dough over every time you take a roll on the rolling pin, sprinkle a little more flour under it, and then roll the other side.
Always keep your rolling pin well floured, too; You want really thin pieces here, absolutely no thicker than your average flour tortilla, otherwise they won't cook all the way through and will taste a little doughy - They should work out to be about nine inches diameter.
Once you have all eight pieces rolled out, heat up your frying pan or griddle and grease it slightly only if it isn't non-stick; Flip one of the uncooked lefse into the pan and quickly unfold any creases that might have happened with the spatula; only turn lefse once, and do it when you see air bubbles forming under the lefse.
It won't need to cook for as long on the other side, but bubbles will form again (harder to see this time, careful not to leave it on too long and burn it!) you can just pick it up with the spatula and check underneath.
Serve warm sprinkled with icing sugar and cinnamon or with some jam.