In a large pot, heat vegetable oil over medium heat. Add chopped onion and cook until softened.
Add garlic and cook for another minute.
Add meat pieces and cook until browned on all sides.
Stir in sliced carrots, diced potato, and chopped bell pepper. Cook for about 5 minutes.
Add tomato paste and cook for another 2 minutes.
Pour in the beef or chicken broth. Add dried thyme, bay leaf, and salt and pepper to taste.
Bring to a boil, then reduce heat and simmer for about 30 minutes, or until vegetables and meat are tender.
If using, stir in sauerkraut or pickled cabbage. Simmer for another 10 minutes.
Remove the bay leaf. Adjust seasoning with salt and pepper if needed.
Stir in sour cream and heat through without boiling.
Garnish with chopped fresh dill or parsley before serving.
Enjoy your meal!