JOZIA'S PIEROGI WITH POTATO-CHEESE FILLING

FOR THE FILLING:
1/2 to 1 cup chopped onion
2 to 3 tablespoons butter
3 cups hot, cooked potatoes, mashed (reserve 1 1/2 cups potato water for making dough)
3 ounces cheddar cheese, cubed or shredded
Salt and black pepper to taste
FOR THE DOUGH:
5 cups flour
2 eggs at room temperature
1 teaspoon salt
1 tablespoon sour cream
1 tablespoon vegetable oil
1 1/2 cups potato water, divided (from potato-cheese filling)
Boiling salted water

TO PREPARE THE FILLING:
In a medium skillet over medium-high heat, saute the onion in butter for 5 minutes. Add the potatoes, cheese, and salt and black pepper to taste. Mix until the cheese is melted. Remove from the heat and allow to cool while making the dough.

TO PREPARE THE DOUGH:
Mound the flour in a large bowl. Add the eggs, salt, sour cream, vegetable oil and 1 cup of the potato water, adding the water last. Add more water from the remaining 1/2 cup if needed. Knead until the mixture forms a ball. Cover the dough with an inverted bowl and let it rest for 15 minutes.

Divide the dough into 3 pieces. Working with one piece at a time on a floured surface, roll out the dough to about 1/8-inch thick. Cut into 3-inch squares or rounds. Place a rounded teaspoonful of the potato-cheese filling on each square or round. Fold over and seal well with fingers or a fork.

Drop the pierogi into boiling salted water (with a little vegetable oil added to it). Return to a boil, then reduce heat and simmer gently for about 5 minutes. Do not overcook or boil too rapidly.

Remove the cooked pierogi and place them on a large platter that is well-greased with butter; turn to coat the pierogi all around. Serve immediately.

(Or if you are making a lot or preparing to freeze them, line a cookie sheet with foil, grease it well, cool one layer of pierogi on the sheet; add a second piece of greased foil; add and cool another layer. Both cooked and uncooked pierogi freeze well, if double-bagged and uncrowded.)

Cook's note: It is important not to under-grease the pierogi, but when boiling the second batch, don't add oil to the salted water. The butter will be enough.

After boiling, the pierogi may be sauteed in a skillet with additional chopped onions and a little butter. They may be served with sour cream and black pepper to taste.

Makes 65 pierogi
Adapted from: Breaking Bread, the Rossi family cookbook (self-published)