Dough: 3 1/2 cups all purpose flour 3 large eggs 2 tablespoons sour cream, buttermilk, or plain yogurt 1 cup water (more if required) butter or oil salt and pepper
Combine flour, half of the water, eggs, and the sour cream, buttermilk or yogurt in a large bowl. Stir vigorously to incorporate the eggs.
Slowly stir in the remaining water until a dough begins to form. Turn out onto a floured surface and knead gently, lifting dough to stretch.
Continue lifting and stretching the dough until the dough is smooth and somewhat sticky inside (I don't know what this actually means; just knead it for a little while), about 3 minutes or so. Do not overwork the dough - if it begins to become elastic, allow it to rest 5-10 minutes under an overturned bowl before working with it again.
When the dough has been kneaded enough, place in a storage bag in the refrigerator to rest 20 minutes, or leave on the counter under an overturned bowl 30 minutes, to allow any gluten which may have developed to rest. (I skip this step, and it still works, but it couldn't hurt)
While the dough is resting, you can prepare the filling.
Filling: (this part is totally up to you; I made up this recipe as I went, but there are all sorts of other filling recipes online) 4 potatoes (boiled, mashed, etc.) 1 sm. onion 2 cloves garlic
Remove the dough from the refrigerator and form it into balls 1 1/2 to 2" in diameter. Roll each out with a rolling pin into a 3-3 1/2" round approximately 1/8 inch in thickness. Cover the ones you've made with a damp paper towel as you work. (It works best if you flour one side and leave one unfloured. Put the filling on the unfloured one so that the edges stick together when you shut it, and the floured side will keep them from sticking together while you're stacking them up before you boil them.)
Hold the dough in one hand, and place a round ball of filling or spoonful into the center. Fold in half to enclose the filling, and pinch the edges securely together. Use water to help with the sealing, if necessary. Don't allow filling to touch the edges to avoid an imperfect seal. Be sure there are no openings along the edges, or the filling will boil out.
Boil a large pot of salted water as you continue to fill the remaining pierogi until all the ingredients run out. As you work, place a sheet of waxed paper dusted lightly with flour or corn meal over and between the pierogi layers until ready to boil.
Cooking: Gently lower pierogi into rapidly boiling water 3-5 at a time and cook for a few minutes until they float to the surface. Remove with a slotted spoon and continue til all are cooked. Saute in butter (or oil)until lightly brown on outside.
An alternative to cooking these in water is to boil them in the broth remaining from a boiled ham, or in chicken broth.
After you boil them, they can be frozen and then reboiled/sauteed later.