Melt 2 Tablespoons of butter in a hot cast iron skillet. Sauté shallots and mushrooms for a few minutes until the mushrooms begin to soften a bit. Add in the sauerkraut, stir and heat through.
Push the mushroom mixture to the outsides of the pan and melt the remaining butter in the middle of the pan. Sprinkle with flour and stir to combine. Add in cream and water, and stir until thickened. Toss with prepared noodles. Sprinkle with fresh parsley if desired.