Add olive oil to a large pot, and heat over medium-high heat. Add the cubed beef to the hot pan. Season with salt and pepper. Brown the meat on all sides until seared and no longer pink. Remove the beef from the pan and set it aside.
Using the same pot, add the sliced onions, and cook for about 8 minutes or until golden. Add a little more olive oil if needed. Add the tomato sauce, beef broth, Hungarian sweet paprika, vinegar, bay leaf, and prepared meat.
Cover the pot and reduce the heat to low. Simmer for 1 hour 45 minutes, or until meat is tender.
Remove from heat, discard the bay leaf, and allow to cool for about 10 minutes while you prepare and boil the noodles. Before serving, taste and add salt and pepper if needed. The stew should be nice and thick. Serve with egg noodles and a dollop of sour cream on the side.
