There is nothing quite like the comfort of pillowy potato-and-cheese pierogi paired with smoky kielbasa and caramelized onions. This casserole brings those familiar flavors together in one hearty dish—without the work of shaping individual pierogi.
The creamy cheddar mashed potatoes are layered with browned kielbasa, sweet onions, and tangy Dijon mustard. A buttery pie-dough crust turns crisp and golden in the oven, giving every serving a satisfying contrast of flaky pastry and creamy filling. Finished with cool sour cream and fresh chives, it is an easy meal for family dinners, potlucks, or chilly evenings.
Recipe Overview
- Prep time: 25 minutes
- Cook time: 25 minutes
- Rest time: 10 minutes
- Servings: 6–8
- Oven temperature: 400°F (200°C)
Ingredients
Potato Filling
- 5 large Russet or Yukon Gold potatoes, peeled and cubed
- Salt, to taste
- 4 tablespoons butter
- ½ cup sour cream or cream cheese
- 1 cup shredded sharp cheddar cheese
- Black pepper, to taste
Kielbasa and Onions
- 1 pound smoked kielbasa, diced
- ½ yellow onion, diced
- 2 tablespoons butter
- 2 tablespoons Dijon mustard
Crust and Assembly
- 1 sheet refrigerated pie dough
- 1 large egg
- 1 tablespoon water
- Butter or cooking spray, for greasing
Garnish
- Sour cream
- Chopped fresh chives
Instructions
1. Make the potato filling
Place the potatoes in a large pot, cover them with salted water, and boil for 15–20 minutes or until fork-tender. Drain thoroughly, then mash with the butter, sour cream or cream cheese, and cheddar. Season generously with salt and black pepper, then set aside.
2. Brown the kielbasa and onions
Melt the butter in a skillet over medium heat. Add the diced onion and kielbasa, then cook until the onion is deeply golden and caramelized and the kielbasa is browned around the edges. Stir in the Dijon mustard until everything is evenly coated. Remove the skillet from the heat.
3. Assemble the casserole
Preheat the oven to 400°F (200°C) and grease a medium baking dish.
Spread half of the kielbasa-and-onion mixture across the bottom of the dish. Add all the mashed potatoes and spread them into an even layer. Spoon the remaining kielbasa mixture over the potatoes.
4. Add the pie-dough crust
Roll the pie dough slightly larger than the baking dish. Lay it over the filling and gently press the edges along the inside rim without stretching the dough too tightly. Trim away any excess.
Cut three or four small slits in the crust to allow steam to escape. Beat the egg with one tablespoon of water, then brush the egg wash evenly over the dough.
5. Bake and serve
Place the casserole dish on a baking sheet to catch any drips. Bake for 20–25 minutes, or until the crust is deeply golden and the filling is bubbling around the edges.
Let the casserole rest for 10 minutes before cutting. This gives the layers time to settle and makes it easier to serve clean slices. Finish each portion with a spoonful of sour cream and a sprinkle of fresh chives.
Helpful Tips
- Drain the potatoes well to prevent a watery filling.
- For an extra-creamy texture, use cream cheese instead of sour cream.
- Allow the onions time to caramelize—their sweetness balances the smoky kielbasa and tangy mustard.
- If the crust browns too quickly, loosely cover it with foil for the remainder of the baking time.
- The filling can be assembled ahead of time. Add the pie dough and egg wash just before baking.
Serving Suggestions
This casserole is rich and satisfying on its own, but it pairs especially well with roasted cabbage, sauerkraut, steamed green beans, or a crisp salad. It is hearty comfort food with all the spirit of homemade pierogi in an easy, shareable form.
