Grandma's Potato Perogies

Steps

1. Add 2 tsp of salt to 4 and 1/2 cups of flour in a large bowl and stir together.
2. In a separate bowl, whisk together 2 tbsp of melted butter with 2 cups of sour cream, two eggs, one egg yolk, and 2 tbsp of vegetable oil.
3. Add the wet ingredients to the dry and stir until well blended.
4. Cover the dough with a kitchen towel and let it rest for 15 to 20 minutes.
5. Place eight peeled and cubed baking potatoes into a large pot and cover with cold water. Season to taste with salt and bring the water to a boil over medium-high heat.
6. Reduce the heat to medium and simmer potatoes until tender, about 15 minutes.
7. To the cooked drained potatoes, add 1 cup of shredded cheddar cheese, 2 tbsp of cream cheese, and season to taste with onion salt and ground black pepper.
8. Mash this mixture together until smooth and set aside to cool.
9. Divide the dough into two balls and roll each one at a time on a floured surface. The thickness should be between 1/8 and a quarter inch, being careful not to make any tears.
10. Cut the dough with a cookie cutter or a glass, 3 to 4 inches in diameter.
11. Brush the outside of the dough with a little bit of water and add a spoonful of the filling to the center.
12. Fold the dough over, forming half circles, and press the edges together to seal. You can use a fork to crimp the edges for a decorative look.
13. Repeat with the remaining dough and filling.
14. To cook pierogies, bring a large pot of lightly salted water to a boil.
15. Lower pierogies into the water in batches and cook until they float to the top, about 5 minutes. Be careful not to overcook them or they'll become soggy.