1. Preheat oven to 375°F (190°C).

2. Peel and dice the potatoes into bite-sized chunks.

3. Slice kielbasa into 1/2-inch rounds and chop the onion.

4. In a large skillet over medium heat, sauté kielbasa slices until lightly browned, about 3-4 minutes.

5. Add onions to the skillet and cook until soft and translucent.

6. In a mixing bowl, stir together the cream of chicken soup, sour cream, milk, garlic powder, black pepper, and 1 1/2 cups of cheddar cheese.

7. In a greased 9×13-inch baking dish, combine diced potatoes, cooked sausage, and onions.

8. Pour the cheese mixture over the top and gently stir to combine.

9. Cover with foil and bake for 50–60 minutes, until potatoes are fork-tender.

10. Remove foil, top with remaining cheese, and bake uncovered for 10–15 minutes until bubbly and golden.

11. Let rest 5–10 minutes before serving.

12. Garnish with chopped parsley, if desired.