I happen to come across this recipe at food.com. HeidiRenee had posted the recipe, but I did tweak the recipe just a bit. I love this casserole, and could eat this at least once a month. It's great comfort food! If you love sauerkraut, then your going to love this dish!!
Grease the inside of a 2-1/2 to 3-quart casserole baking dish; set baking dish aside.
Cook egg noodles as per directions on package; set aside.
Cut Kielbasa or smoked sausage into chunks, then cut each chunk in half; set aside.
Melt the 1/3 cup of butter in a large saucepan. (I used a 3-quart saucepan).
Stir in the flour, garlic power, onion powder, pepper, and mustard.
When mixture is well combined, gradually add the milk. Bring mixture to a boil for 1 minute; stirring constantly until the sauce has thicken. (Mine started to thicken in less than a minute.)
Add the cup of cheese to the pan, stir until melted.
Add the Kielbasa or smoked sausage, plus the drained sauerkraut to the pan, and stir.
Pour mixture into the greased baking dish, then stir in the precooked noodles.
Top the casserole with a mixture of 4 tablespoons of bread crumbs mixed with 2 tablespoons of melted butter.
Bake casserole (uncovered) for 25 minutes in a 375º oven.
Note: When preparing this casserole, you can use a Bavarian Sauerkraut in place of regular sauerkraut. Plus the original recipe states to use 2 cups of the kraut, but I just use 1-1/2 cups. Also, you can use smoked sausage in place of the Kielbasa. I used smoked sausage, and the brand of sausage I used was, Eckrich.