- 1 box frozen potato and cheddar pierogies
- 1/2 Polish kielbasa, halved and sliced
- 1 onion, thinly sliced
- 2 1/2 tablespoons butter, divided
- 1 1/2 tablespoons flour
- 1 1/2 cups milk
- 1 1/4 cups cheddar cheese, shredded
- Salt and pepper
- 1/4-1/2 cup cheddar cheese, shredded
Preheat oven to 375 degrees.
Spray the inside of a baking dish (9×13 or smaller) with cooking spray. Line the bottom of the dish with the frozen pierogies.
To prepare the onions, heat one tablespoon of butter in pan over medium heat. Add the onions. Cook for about 10 minutes, stirring frequently, until the onions are tender, sweet, and golden brown. Scatter the onions over the frozen pierogies.
Scatter the kielbasa slices over the onions.
To prepare the sauce, melt the remaining 1 1/2 tablespoons butter in a pan over medium heat. Stir in the flour until well-blended. Cook for a minute or two. (This is your roux, which will help to thicken the sauce.) Gradually add the milk, whisking until smooth. Bring the mixture to a simmer and cook for 2-3 minutes until it begins to thicken. Reduce the heat to low and add the cheddar cheese. Stir until melted. Season with a touch of salt and pepper. (Be careful not to over-salt the sauce, since the kielbasa will add a good amount of salty flavor to the finished dish.)
Pour the sauce over the mixture in the baking dish. Sprinkle the remaining cheese on top.
Bake for about 40 minutes.