Preheat oven to 400 degrees (F).

Grease the bottom and sides of a 9x13 inch pan.

Grate the parboiled potatoes.

Mold the grated potatoes into the bottom and sides of the greased pan.

Season with salt and pepper to taste.

Place the pan in the oven for 20 minutes.

While the potatoes are baking, mince the onions.

Pan fry the minced onions until they are translucent.

Chop the cooked polska kielbasa into bite-sized pieces.

Add the chopped kielbasa to the pan with the onions.

Blend the eggs, garlic powder, and yogurt (or sour cream) with a stick blender for a couple of minutes until fluffy.

Remove the pan from the oven carefully.

Reduce the oven heat to 350 degrees (F).

Add the cooked polska kielbasa, cooked onions, and half of the grated cheese to the pan with the potatoes.

Pour the egg mixture over the ingredients in the pan.

Return the pan to the oven and cook for approximately 30 minutes, gently stirring egg layer once after 15 minutes to ensure even cooking.

Top with the remaining cheese.

Broil until the cheese is melted and bubbly.

Serve hot!