Pat the beef cubes dry and season generously with salt and pepper. In a large Dutch oven over medium-high heat, heat the vegetable oil. Sear the beef in batches until deeply browned on all sides. Remove from the pot and set aside.

Reduce heat to medium, add the butter, then the sliced onions. Cook until soft and golden, about 10-15 minutes. Add the minced garlic and cook for 1 more minute until fragrant.

Stir in the tomato paste and cook for 2 minutes. Add the sweet paprika, smoked paprika, caraway seeds, and marjoram, stirring constantly for 30 seconds to toast the spices.

Return the beef to the pot. Pour in the beef broth and scrape up any browned bits. Bring to a simmer, then reduce heat to low, cover, and cook for 1.5-2 hours, or until the beef is fork-tender.

Remove the pot from the heat. Temper the sour cream by whisking a few tablespoons of the hot broth into it, then stir the mixture back into the goulash. Add the lemon juice and season with more salt and pepper to taste. Garnish with fresh parsley before serving.