Step 1

Preheat oven to 350°F and grease a 9x13-inch baking dish with butter or nonstick spray.

Step 2

In a large pot of salted water, cook pasta according to package directions. Drain and set aside in a large bowl.

Step 3

In a large saucepan, melt the butter over medium heat. Whisk in the flour and let cook 1 minute, stirring constantly.

Step 4

Gradually whisk in milk, stirring constantly, and cook until thickened. Remove from heat, stir in garlic powder, Dijon mustard, and sour cream, and season with salt and pepper.

Step 5

Pour sauce over pasta, and add the sauerkraut, sausage, green onions, and 2 cups of the cheese. Pour into prepared baking dish and top with remaining cheese.

Step 6

Bake until golden brown and bubbly, 30-40 minutes. Let rest 5 minutes before serving. Enjoy!