In the bottom of the crockpot, layer half of the frozen pierogi.

Add half of the sliced kielbasa on top of the pierogi, followed by half of the diced onion and half of the sauerkraut.

Sprinkle half of the shredded cheddar cheese over the layers.

In a small bowl, mix together the sour cream, garlic powder, onion powder, paprika, salt, and pepper. Spread half of this mixture over the cheese layer.

Repeat the layers with the remaining pierogi, kielbasa, onion, sauerkraut, and cheddar cheese. Top with the remaining sour cream mixture.

Cover and cook on low for 6-8 hours or on high for 3-4 hours, until the pierogi are tender and the kielbasa is heated through.

Before serving, garnish with fresh chopped parsley.