Place flour and salt in a bowl and stir until combined.
2 3/4 cups flour, 1/2 teaspoon salt
Add egg, oil, and water and stir until a soft dough forms. Knead by hand or with a dough hook until softly elastic.
1 egg, 2 teaspoons oil, 3/4 cup warm water
Let the dough rest for 15-20 minutes, covered with a barely damp cloth. Start water boiling while dough rests.
Have filling prepared (see notes) and ready to go, then roll dough on floured surface until 1/8" thick. Use a large biscuit cutter to cut out a few rounds at a time.
Gently stretch the rounds, being careful not to rip the dough. Place a teaspoon of filling into the center of the round. Pull edges out and towards each other, crimping together as you go.
Make 3-4 pierogies, then add them to pot, while you make the next pierogi. Remove finished pierogies from water as you add new ones.
When the pierogies float to the top, use a slotted spoon or spider to remove, then drain in a colander without touching.
Use melted butter in a large pan to prevent them from sticking. Cover the storage container after you add each one to keep them warm. Serve immediately with garnishes, as you choose.
Meat filling: Brown one pound of ground beef (or use leftover ground beef - turkey, pork or veal work, too - or any combination of the above). Drain the meat and add to a food processor. Chop a medium onion and add it to the food processor. Pulse 10 to 15 times, until the mixture is fully combined and the onions are minced. Add 1 egg and 3/4 c chicken or beef stock. Pulse another three to four times, and your filling is ready. Feel free to make this in advance and pull it from the fridge when you are ready to make your pierogies. The filling isn't pretty, but it's incredibly tasty.
Traditional potato and cheese filling: Peel three smallish (or 2 large) baking potatoes. Cut and boil them as if you were going to make mashed potatoes. Rice them, add a touch of chicken stock, and stir to make thick mashed potatoes. Add 1/4 c shredded cheddar cheese and stir again until the cheese has melted. If you don't have a ricer, mash as you usually would - the ricer keeps them airy and fluffy. Eliminate the cheese or use a vegan cheese to keep them dairy free.
For more tips and tricks, be sure to read the full article above.