Start soaking the beans for at least 6 hours. Strain them, put them in a saucepan with water and boil them until they soften for about 1-1.5 hours.
In a saucepan pour 1/4 cup. vegetable broth and bring to a boil. Add the onion, garlic and all the spices for the beans and sauté until the onions are soft.
Add the tomato, turmeric, paprika, cayenne pepper and garam masala. Stir and cook for 5 minutes.
Add the beans and 2 tbsp. water from boiling beans. If you have not kept you can put vegetable broth. Boil on low heat for 10 minutes. Add salt and set aside.
Put the vegetable broth and sweet potatoes in a wok or non-stick pan. Once they get a boil add the orange juice, garam masala and black pepper. Mix and cover. Cook for 10-12 minutes. If you save water, add a little more.
Add salt and set aside.
Serve your beans with the sweet potatoes.