Season the beef cubes with salt and pepper.
In a large pot or Dutch oven, heat the vegetable oil over medium heat. Add the chopped onions and cook until they are golden brown and caramelized, about 10-15 minutes.
Add the minced garlic and cook for another minute. Stir in the sweet paprika, tomato paste, caraway seeds, marjoram, and ground black pepper. Cook for a few more minutes, allowing the spices to become fragrant.
Add the seasoned beef cubes to the pot and cook until browned on all sides.
Pour in the beef broth and water, stirring to combine. Bring the mixture to a boil, then reduce the heat to low and let it simmer, covered, for about 1.5 to 2 hours, or until the beef is tender.
Add the diced potatoes, red bell pepper, and green bell pepper to the pot. Continue to simmer for another 30 minutes, or until the vegetables are tender.
Stir in the white vinegar and adjust the seasoning with additional salt and pepper if needed.
Ladle the goulash into bowls and garnish with freshly chopped parsley. Serve with a dollop of sour cream if desired.
Enjoy your meal!