Soak beans overnight. Rinse and drain the excess water. Place the beans in a pot with 3 cups of water and boil on medium heat for 30-40 minutes or until soft and tender
Heat 2 tablespoon oil in a pot on medium heat. Add the mustard seeds. Once the seeds pop, add the bay leaf, cinnamon stick and star aniseed. When fragrant, turn the heat to a low setting, add the curry leaf and onion. Fry until onion is golden brown
Add ginger garlic paste and cook for a minute
Add the cumin, coriander, turmeric, fennel and masala. Fry for 2 minutes. Add a few drops of water if required
Add the potatoes and allow it to cook on low heat for 5 minutes. Season with salt. Add a few drops of water to prevent scorching
Add the tomatoes. Cover the pot and cook for 5 minutes. Add half cup of water and allow the potatoes to simmer until slightly tender. Add more water in between cooking time only if required
Mix the tamarind in 1/4 cup warm water and add it to the potatoes together with the beans. Add a pinch of sugar
Cook for 5 minutes and add 1 cup of water. Use your discretion in terms of how much water you require as this depends on how thick you would prefer the gravy.
Simmer on low heat until potatoes are fully cooked.
You can add a tablespoon of butter towards the end of cooking if you want to be indulgent
Add some fresh, chopped coriander and serve hot