Prepare the Crockpot
Lightly grease the inside of your crockpot to prevent sticking.
Layer the Ingredients
Add one package of frozen pierogies to the bottom of the crockpot. Top with half of the sliced kielbasa.
Mix the Sauce
In a mixing bowl, combine cream of chicken soup, sour cream, shredded cheddar cheese, cream cheese, garlic powder, onion powder, salt, and pepper. Mix until smooth and well combined.
Assemble the Casserole
Pour half of the sauce mixture over the pierogies and kielbasa. Add the second layer of pierogies, kielbasa, and the remaining sauce.
Cook the Casserole
Cover and cook on low for 4–5 hours or on high for 2–3 hours. Stir gently halfway through cooking to ensure even coverage.
Serve and Garnish
Once the pierogies are tender and the cheese is melted, garnish with fresh parsley if desired. Serve hot and enjoy!