Pierogi-Stuffed Shells with Creamy Potato & Cheddar Filling

Easy Pierogi Stuffed Shells are jumbo pasta shells filled with cheesy mashed potatoes, topped with sautéed onions and plenty of cheddar. This simplified pierogi casserole delivers the same comforting flavors as traditional pierogies without the time-consuming dough — perfect for a family weeknight dinner.

I love classic cheesy potato pierogi — my family makes homemade pierogi at Christmas using my grandmother’s recipe. Because the traditional method is labor intensive, I created this lazy pierogi version: jumbo shells stuffed with a cheesy mashed potato filling. The result tastes like pierogies but is much quicker.

Ingredients

These simple ingredients are easy to find and make the dish quick to prepare:

• Jumbo pasta shells (about 12 oz)
• 1 medium yellow onion, chopped
• 4 tablespoons butter (plus more if desired)
• 3 cups mashed potatoes (leftover or freshly made)
• 4 cups shredded cheddar cheese or a cheese blend, divided
• Salt and black pepper to taste
• 1/4 cup water or broth (optional, for softer shells)

Leftover mashed potatoes work great here. You can also use store-bought mashed potatoes or prepare instant or from-scratch mashed potatoes.

How to Make Pierogi Stuffed Shells

Begin by cooking the jumbo shells according to package directions. Drain and place them on a greased baking sheet so they cool slightly and are easier to stuff.

While the shells cool, melt butter in a large skillet and sauté the chopped onion over medium heat until it turns a light golden brown. You want some color, but not full caramelization.

Warm the mashed potatoes in a microwave-safe bowl if using leftover chilled potatoes. Stir in 2 cups of the shredded cheddar until well blended. Season with salt and pepper to taste.

Fill each shell with about 2 tablespoons of the potato-cheese mixture, and arrange the stuffed shells, open side up, in a greased 9×13-inch baking dish. Pack them closely in a single layer; if you have extra shells, use a second smaller dish.

Pour the sautéed onions and any remaining butter evenly over the shells — this adds the signature pierogi flavor. Sprinkle the remaining 2 cups of shredded cheese over the top. If you prefer softer or saucier shells, add 1/4 cup of water or broth to the bottom of the baking dish before baking.

Cooking Time

Preheat the oven to 350°F (175°C). Bake the stuffed shells for about 30 minutes, or until the cheese is melted and the shells are heated through. If the cheese melts before the shells are hot, cover loosely with foil and continue baking until warmed.

Variations

This recipe is flexible — feel free to customize:

• Use a four-cheese blend, parmesan, or mozzarella instead of cheddar.
• Mix in cream cheese for a richer, creamier filling.
• To reduce cheese, skip mixing cheese into the filling and only top the shells with cheese.
• Make it dairy-free by using vegan butter, non-dairy cheese, and plant-based mashed potatoes.
• Substitute dried minced onion or onion powder if you don’t have fresh onion.
• Add red pepper flakes, paprika, or sliced jalapeños for heat.
• Garnish with green onions, sour cream, or bacon bits for serving.
• Try a pierogi lasagna variation using lasagna noodles and béchamel instead of shells.

How to Store and Reheat

Store leftovers in an airtight container in the refrigerator for 3–4 days. For longer storage, freeze in a freezer-safe container. You can assemble the stuffed shells ahead of time and refrigerate or freeze them, then bake when ready to serve.

Reheat single portions in the microwave. For larger portions or frozen batches, reheat in the oven until warmed through.