Start by boiling a large pot of salted water.

Once the water is boiling, add the frozen pierogi and cook according to package instructions, usually about 5-7 minutes.

Carefully drain the pierogi in a colander and set them aside.

In a large skillet, melt 2 tablespoons of butter over medium heat and add the diced onion.

Sauté until the onions are soft and golden, about 5-7 minutes.

Add the drained pierogi to the skillet with the sautéed onions.

Cook the pierogi for about 5-7 minutes, flipping occasionally, until they are golden and crispy.

Season the pierogi with salt and pepper to your liking.

Remove from heat and serve hot, with a generous dollop of sour cream on the side.