Preheat oven to 375°F. Grease a 9x13-inch baking dish with butter or nonstick spray.
Heat a skillet over medium heat and add 14 ounce package kielbasa, diced. Cook for 4–5 minutes, stirring occasionally, until lightly browned. Remove from heat and set aside.
Place 2 (16 ounce) boxes frozen potato pierogi into the prepared baking dish in a single layer. Set aside.
In a mixing bowl, whisk together ¾ cup chicken broth, ¾ cup half and half, ½ teaspoon salt and ½ teaspoon freshly ground black pepper until well combined.
Pour the sauce evenly over the pierogi. Top with the browned kielbasa slices, then sprinkle 1 cup shredded cheddar cheese on top.
Cover the baking dish with foil and bake for 20 minutes. Remove the foil and bake for an additional 10 minutes, or until the cheese is melted and bubbly and pierogi are cooked through.
Optional: sprinkle with fresh parsley, chopped before serving.
Notes
Please refer to my FAQ’s (Frequently Asked Questions) and ingredient list above for other substitutions or for the answers to the most common questions.
The chicken broth is being used to steam the pierogi. It's not necessarily making a sauce but you need to have a liquid in order for the pierogi to steam and cook up soft and tender so it will stay at the bottom of the pan after cooking. I still spoon up some of that when serving.
I was trying to keep this recipe as simple as possible for a quick weeknight dinner. You can certainly add more ingredients to this casserole. You can add additional seasonings like onion powder and garlic powder. You could add in drained sauerkraut, steamed broccoli, etc. to fill out the dish more.