In a 4-6 quart crockpot, add 3 cups of chicken broth, frozen pierogies, sliced kielbasa, and shredded cheddar cheese. Stir to distribute the ingredients evenly.

Set the crockpot to cook on high for 3-4 hours or low for 6 hours.

About 30 minutes before the casserole finishes cooking, warm the cream cheese with the remaining 1 cup of chicken broth, either in the microwave or on the stovetop. Whisk until smooth.

Pour the cream cheese mixture into the crockpot and stir well to combine. Sprinkle the remaining shredded cheddar cheese on top. Cover and cook on low for another 30 minutes.

Serve hot, optionally garnished with sliced green onions.