Start by slicing the onions into long thin pieces. Then heat the butter and olive oil in a pan over medium heat. Add the onions and baking soda and sauté the onions over medium low heat until they reach a golden brown color. This will take about 20-30 minutes.

While the onions are cooking, prepare the pierogi. Microwave the potatoes according to the directions on the bag.

Then in a large bowl, combine the ingredients for the dough, and stir together until smooth. This can be done by hand instead of with an electric mixer. Cover the dough with plastic wrap while you prepare the potatoes.

Once the potatoes have cooked, pour them into a bowl. Add the cheese, milk, butter, sour cream, and a dash of salt and pepper. Then mash the potatoes.

Use a rolling pin to roll out the dough. Roll out the dough until it is ¼ inch thick. Then use a biscuit cutter or a glass to cut 3 inch rounds. Scoop one tablespoon of potato into the center of each round. Fold the dough in half, pinch the edges together, dip the edges in warm water, and seal closed with a fork.

Bring a pot of water to boil. Add the pierogis to the water, and cook until the float.

Then remove from the water with a slotted spoon and let drain.

Heat enough butter and olive oil to coat the bottom of a skillet. Then add the cooked pierogi to the skillet and cook each side until golden brown, this will take about 2 minutes.

Serve the browned pierogi with a scoop of caramelized onions on top.