Follow these simple steps to prepare your casserole:

1. Begin by spraying your crockpot with non-stick cooking spray to prevent sticking.
2. Place half of the frozen pierogi in the bottom of the crockpot.
3. Layer half of the sliced kielbasa over the pierogi.
4. In a mixing bowl, combine the sour cream, cream of mushroom soup, chopped onion, minced garlic, paprika, salt, and pepper. Stir until well blended.
5. Spoon half of the sour cream mixture over the kielbasa layer.
6. Sprinkle half of the shredded cheddar cheese over the sour cream mixture.
7. Repeat the layers with the remaining pierogi, kielbasa, sour cream mixture, and cheese.
8. Cover the crockpot with its lid and set it to cook on low for 4-5 hours, or until the pierogi are tender and the cheese is bubbly.
9. Once cooked, garnish with fresh parsley before serving.

As a tip from Mama Lou, always taste and adjust the seasoning before serving. Her secret was a pinch of love in every dish, which I like to think is just a bit more salt to enhance the flavors!