Add 4 cups of pasta of your choice (such as fusilli, penne, or rotini) to the boiling water.
Cook the pasta according to the package instructions until it is al dente (firm to the bite).
Once cooked, drain the pasta and set it aside.
Prepare the Sauce:
In a large saucepan, melt 2 tablespoons of butter over medium heat.
Stir in 2 tablespoons of flour and cook for 1-2 minutes until lightly golden.
Gradually whisk in 2.5 cups of milk, stirring constantly until the sauce thickens.
Remove the saucepan from the heat and stir in 1 cup of sour cream, 2 tablespoons of Dijon mustard, and 1 teaspoon of garlic powder until well combined.
Preheat the Oven:
Preheat your oven to 375°F (190°C).
Assemble the Casserole:
In a 9×13-inch baking dish, layer half of the cooked pasta on the bottom.
Add a layer of sauerkraut, followed by a layer of sliced Polish sausage or kielbasa.
Sprinkle half of the grated Swiss cheese (about 1.5 cups) over the sausage layer.
Pour half of the prepared sauce evenly over the layers.
Repeat the Layers:
Repeat the layers with the remaining ingredients: pasta, sauerkraut, sausage, cheese, and sauce.
Bake the Casserole:
Place the assembled casserole in the preheated oven.
Bake for approximately 30 minutes, or until the cheese is melted and bubbly, and the casserole is heated through.
Serve and Enjoy:
Once baked, remove the casserole from the oven and let it cool for a few minutes.
Serve the Polish Pasta Casserole hot, and enjoy the delicious flavors!
