Potato Knishes

Step 1: Slowly cook the onions in the oil in a skillet, covered, over a low heat (allow the onions to "sweat" for about 20 minutes, or until they are soft). Remove the cover and fry over a medium heat until golden brown. Don't drain the oil.

Step 2: Meanwhile peel the potatoes and cut them in half. Put them in a large pot filled with cold water and salt to taste. Bring to a boil, then turn the heat down, and cook until soft, about 15 minutes. Drain and cool for 5 minutes.

Step 3: Mash the potatoes and add the egg, the parsley, 2 teaspoons of salt, and pepper. Add the onions with the oil and mix well with your hands. Set aside while preparing the dough (this all can be prepared a day in advance).

Step 4: FOR DOUGH; Beat the eggs and reserve about 1 tablespoon of egg for the glaze. Mix the rest with the oil, water, vinegar, and salt. Add the flour gradually, beating first with a spoon and eventually your hands as you knead the dough. Continue to add enough flour to make a smooth dough. Shape into 4 balls and let rest, covered with a cloth, about a half hour to relax the gluten.

Step 5: Roll each ball of dough out as thin as possible into a flat rectangle. Flour well and place between 2 sheets of waxed paper. Let sit for about 15 minutes.

Step 6: Using your hands carefully stretch each rectangle as thin as possible, about 12 to 14 inches long by 4 to 5 inches wide.

Step 7: Spread one quarter of the filling (about 1 1/2 cups) onto approximately one third of the dough, leaving a 1-inch border.

Step 8: Holding onto the waxed paper, roll up the dough like a jelly roll, brushing oil across the top a couple of times as you roll. Using the side of your hand like a knife, divide the roll into 2-inch knishes. Then pinch the open ends shut. Repeat with the remaining balls and dough.

Step 9: Place the knishes, flat side down, on a greased cookie sheet, leaving a 2-inch space between each. You will have to bake in batches.

Step 10: Mix the reserved tablespoon of egg with a little water. Brush the tops with the egg wash.

Step 11: Bake in a preheated 375F oven for 25 to 30 minutes or until golden brown.