Grease the inside of your slow cooker with a light layer of cooking spray or olive oil, then layer the bottom with frozen hash browns, diced kielbasa, and chopped onion.

In a medium bowl, combine cream of mushroom soup, sour cream, and creole seasoning. Add salt and pepper to taste, stirring until creamy.

Pour the creamy soup mixture over the layered hash browns, sausage, and cheese in the slow cooker, gently stirring to distribute evenly.

Sprinkle the remaining cup of cheddar cheese on top of the casserole mixture.

Cover the slow cooker and set to cook on low for 6 hours or high for 4 hours.

After cooking time, check for doneness; the potatoes should be fork-tender and the cheese melted.

Scoop the casserole into bowls and serve hot, possibly with scrambled eggs or a crisp salad.