Knead the dough well until smooth and elastic, adding a little flour if sticky or a drop of water if necessary. Wrap in plastic wrap and allow to rest 20 minutes.

Fry the onion in oil till soft. Add the meat, season with salt and pepper, and cook, stirring and crushing the meat with a fork, until it changes color. Let it cool a little, then put it in the food processor with the egg and parsley and blend to a paste.

Roll out the dough as thin as possible on a lightly floured surface and cut it into 2½-inch (6½-cm) squares. The Jewish way to do it (as opposed to the Italian) is to fold the sheet of dough over and over into a flattened scroll, and to cut across into pieces 2½ inches (6½ cm) wide. Then unroll the strips, put them in a pile, and cut them into squares. Scraps can be rolled into a ball, rolled out again, and cut into squares.

Put a teaspoon of filling in the middle each square and fold over diagonally, bringing one point to meet the opposite point to make triangle. Pinch the edges together firmly to seal tightly. Now make a ring by bringing the two longer points of the triangle together and pressing them firmly to stick them. Leave to stand 15 minutes.

Drop the kreplach in plenty of boiling salted water and cook over medium heat for about 20 minutes. Start with a fast, hard boil to prevent them from sticking to the bottom, and when they float to the top, continue cooking on medium heat. Remove the cooked dumplings with a slotted spoon. When you are ready to serve, drop them into the chicken broth. (You can cook them in the broth, but they give it a cloudy appearance.)

Variations:

You can make kreplach with leftover cooked beef or chicken mashed to a paste in the food processor with parsley and seasonings.

For kreplach with a chicken-liver filling (also called “varenikes”): Fry 1 small chopped onion in 2 tablespoons of oil until soft, Sprinkle 6 oz (175 g) chicken livers with salt and sear on both sides under the grill to kosher them. Blend lightly in the food processor with 1 small egg and a little pepper. A wonderful Hungarian version is made with goose liver.

For a mushroom filling: Fry 1 small chopped onion in 2 tablespoons of oil, then add 6 oz (175 g) mushrooms (preferably shiitake) that have been finely chopped in the food processor. Sauté gently, adding salt and pepper and a little water, until thoroughly cooked and the liquid is absorbed. Add 2 tablespoons finely chopped parsley. Bind with a beaten egg added in at the end. There are those who mix in a little mashed potato to bind the hash into a paste, making it easier to use.