From Jewish Home Cooking by Arthur Schwartz
3 Tbsp oil
3-4 lbs boneless beef chuck (only about 1/4 will be used in kreplach, serve the rest as a roast)
4 cups coarsely chopped onion
2 cloves garlic, coarsely chopped
2 carrots, peeled
2 celery ribs, halved crosswise
1-1/2 tsp salt
1/2 tsp pepper
Heat the oil in a Dutch over over med-high heat. Sear the meat on all sides until well browned. Removed meat and set aside.
Reduce heat to medium. Add onion. Sauté until tender and lightly colored, 10-12 min. Add garlic for the last few minutes.
Return the meat to the pan. Arrange carrots and celery around it. Add enough water to come half-way up the side of the meat. Add salt and pepper. Raise heat to med-high. Bring to a simmer, cover, and simmer gently for 2-1/2-3 hours. Check after two hours that there is still water in the pot.
Let meat cool in the pot. Refrigerate until ready to use. Discard the carrots and celery. Finely mince 1/4 of the meat, juices, onions, and garlic, by hand or in a food processor. It should be slightly stringy, not pasty. Slice and serve the remaining meat separately.
2 cups flour
2 Tbsp lukewarm water
Put the flour in a large bowl. Make a well and add the eggs and water. With a fork, beat the eggs and water, incorporating some of the flour. When well blended, knead on a lightly floured board. Form into a ball, cover and rest for 30 minutes.
Roll the dough very thin, half at a time, on the board. Cut into 3-inch squares. Put no more than 1 tsp filling in the center. Brush the edges with water and fold into a triangle, fold again if preferred.
Cook in a large pot of well-salted water. Boil 6-8 minutes until dough is tender. Drain and cool. Reheat in chicken soup.