Blend the tomato, ginger and chilli to a paste. In your pressure cooker, heat ghee (about 1 tbsp), then add the cumin and hing. Heat until it darkens a few shades, then add the paste and turmeric and cook until very fragrant and the oils separate.
Add in the salt, toor dal, water and potato, and the water. Cook on a low pressure setting for 15 minutes. When cooked, stir in the amchoor and garam masala.
Serve sprinkled with chopped coriander.
Put the beans (and can juice), onion, garlic, chilli and cumin into a saucepan with the stock. Bring to boil, then reduce heat and cook, stirring intermittently, until it thickens.
Take off the heat and stir in the lime juice, and the chopped coriander root/stems. Add salt to taste (you probably won’t need it).
Serve with coriander leaves roughly chopped on top.