Preheat your oven to 375°F and lightly grease a 9x13 inch baking dish.

Arrange half of the frozen pierogies in a single layer in the prepared baking dish.

Pour half a cup of heavy cream over the pierogies, then sprinkle with half of the crumbled bacon, half of the sliced green onions, and half of each type of shredded cheese.

Repeat the layering with the remaining pierogies, heavy cream, bacon, green onions, and cheeses.

Season the top layer with salt and pepper to your liking.

Cover the dish with aluminum foil and bake in the preheated oven for 25 minutes.

Remove the foil and continue to bake for an additional 20 minutes, or until the cheese is melted and bubbly and the pierogies are heated through.

Let the casserole stand for a few minutes before serving.