Pat the beef chuck roast cubes thoroughly dry with paper towels. Season generously with salt and freshly ground black pepper. Heat the olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat until shimmering. Working in batches, sear the beef on all sides until deeply golden brown. Remove the browned beef to a plate and set aside.

Reduce the heat to medium. Add the diced onions to the pot, scraping up any browned bits from the bottom. Sauté for 8-10 minutes, stirring occasionally, until the onions are soft, translucent, and just beginning to caramelize. Stir in the minced garlic and diced red bell pepper (if using). Cook for another 2-3 minutes, until fragrant.

Remove the pot from the heat briefly. Stir in the sweet Hungarian paprika and flour. Cook for 1 minute, stirring constantly, until a fragrant paste forms. Return the pot to the heat. Gradually pour in the beef broth, scraping the bottom of the pot to loosen any remaining browned bits. Stir well to combine. Add the diced tomatoes, browned beef, caraway seeds (if using), and bay leaves (if using). Bring the mixture to a gentle simmer.

Reduce the heat to low, cover the pot, and simmer for 2 to 2.5 hours, or until the beef is fork-tender. Check periodically and give it a stir to prevent sticking. If the sauce becomes too thick, you can add a little more beef broth or water. Once the beef is tender, remove the bay leaves. Taste and adjust seasoning with salt and pepper as needed. Remove the pot from the heat and let it cool for a few minutes. In a small bowl, whisk the sour cream until smooth. Stir a ladleful of the hot sauce into the sour cream to temper it, then gently stir the tempered sour cream into the pot until fully incorporated and creamy.

Ladle the rich, creamy beef paprikash generously over hot egg noodles or spaetzle. Garnish with fresh parsley or dill and serve.