Heat a 4-quart sauce pot over medium heat and add the butter and olive oil. Add the salt, paprika, cumin, ground coriander, red pepper flakes, and caraway seeds. Cook for a minute or two, then add the onion, red bell pepper, and garlic. Saute for about 5 minutes or until soft, stirring often.
Add the carrots and potato. Continue to cook for about 5 minutes more or until the potatoes are cooked through. Stir as needed to keep vegetables from sticking to the pan.
Add the tomato paste and stir throughout the vegetables.
Add the broth and tomato juice. Reduce heat to medium low and simmer 20 minutes.
Stir in the chopped mint and simmer for another 2-3 minutes.
For serving, garnish with Greek yogurt and juice from lime wedges.