1. 1. Start by heating the olive oil in a large pot over medium-high heat. Working in batches, brown the beef cubes on all sides, about 2-3 minutes per batch. Remove the beef from the pot and set it aside.

2. 2. In the same pot, add the chopped onions and cook until softened, about 5-7 minutes. Stir in the sweet paprika, smoked paprika, caraway seeds, marjoram, and cayenne (if using). Cook for 1-2 minutes until fragrant. Add the minced garlic and tomato paste, and cook for an additional minute.

3. 3. Pour in the red wine (if using) and beef broth, scraping up any browned bits from the bottom of the pot. Return the browned beef to the pot and bring to a boil.

4. 4. Stir in the diced tomatoes, bell peppers, and cubed potatoes. Reduce heat to low, cover, and let simmer for 1-1.5 hours until the beef is fork-tender and the potatoes are cooked through.

5. 5. In a small bowl, whisk together the sour cream and flour until smooth. Gently stir this mixture into the goulash and cook for an additional 5-10 minutes until thickened. Season with salt and pepper to taste.

6. 6. Ladle into bowls and garnish with parsley. Serve over noodles or Spätzle if desired.