First, start by peeling and cubing some russet potatoes...
add some salt and water and boil them until tender.
Open the bottle of sauerkraut and dump it in a pot.
Set the bottle aside for now. Add some water to the kraut. The less water you add, the more sour it will be.
Let the sauerkraut boil for about 15 minutes. Then, add equal parts cold water and flour in the jar. Put the lid on and shake the heck out of it.
It should be thick but creamy. Not too thick, not runny.
Pour it into the boiling kraut and stir with a wisk until thickened.
Add salt and pepper to taste. Stir well.
Turn off the heat and let it rest.
Drain the potatoes
Dish up some potatoes and then spoon some sauerkraut over them. Enjoy!