Cut beef into small cubes. Peel and slice onions into thin rounds. Heat a large pan over high heat and add 1 Tbs. oil, swirl to coat. When oil is good and hot, add onions and cook until lightly browned, about 5 minutes, stirring often. Remove onions to a soup pot.
Add another tablespoon of oil. When hot, add 1/3 of the beef. It is important not to crowd the pieces, so the browning is best done in 2-3 batches. Brown beef for about 5 minutes (brown on both sides), add to soup pot, then add more beef and continue to brown. Add a little more oil if necessary to keep things from sticking. When the final batch is mostly brown, add the paprika and the cayenne pepper, fry an extra minute, remove to soup pot. Add water. Make sure to pour 1/2 cup into used frying pan and scrape up the browned bits and pour into the soup pot. Add the bay leaves and bring soup to a simmer, simmer for 1 hour.
Peel and cut potatoes, add to soup along with salt, which this soup frankly needs alot of. Start with 1 Tablespoon and adjust as needed. Raise the heat to medium (soup should not quite boil) and cook for another 45 minutes. Serve with a simple salad and fresh crusty white bread, so you can dunk it into the soup. Let each person add their own pepper to taste when it is served.