In a Dutch oven, melt butter over medium-high heat. Add to it: sauerkraut, onion, and celery. Cook, stirring frequently until the onion is translucent and celery is cooked. About 20 minutes.
While sauerkraut mixture is cooking, boil your Kluski noodles in a pot of salted boiling water. Drain.
Stir noodles into the sauerkraut mixture.
Cover and bake for 30 minutes. Remove lid and bake for 15 minutes more. Noodles will begin to turn golden brown on top.
Serve right from the pot, top with scallions, if desired.