This is from Mr. Food.

They say to serve it with kielbasa.

Pierogi Lasagna

12 lasagna noodles
1/3 cup vegetable oil
5 medium-sized onions, finely chopped (about 3 cups)
1/2 teaspoon black pepper
1 1/2 cups (6 ounces) shredded Cheddar cheese
6 cups warm seasoned mashed potatoes, store-bought or homemade

What To Do:

Preheat oven to 350 degrees F. Coat a 9- x 13-inch baking dish with cooking spray.

Cook lasagna noodles according to package directions; drain and set aside.

Meanwhile, in a large skillet, heat oil over medium-high heat. Saute onions 8 to 10 minutes, or until lightly browned; reserve 1/2 cup sauteed onions for topping. Add remaining onions, pepper, and cheese to mashed potatoes; mix well.

Place 3 noodles on bottom of prepared baking dish. Spread 1/3 of potato mixture over noodles. Repeat layers until a total of 4 layers of noodles and 3 layers of potato mixture have been placed (with a layer of noodles on top). Top with remaining sauteed onions.

Cover with aluminum foil and bake 25 to 30 minutes, or until heated through.

Note:

You might want to add a few cooked sliced mushrooms to the potatoes, or maybe a cup of well-drained sauerkraut. And season your mashed potatoes however you like 'em...salt, pepper, and butter work fine.