If you bought frozen gawar or cluster beans, thaw them before starting.
Heat oil in a saucepan, and add onions. Fry onions on medium heat for 3 minutes.
Add cumin seeds and fry till aromatic.
Add ginger and garlic paste.
Continue to fry onions till they are soft and translucent.
Add a splash of water to deglaze the pan, and add diced tomatoes. Fry tomatoes and adding remaining spices and salt.
Once the tomatoes have softened, add gawar. Lightly fry for a few seconds.
Add the diced potatoes, and coat in masala.
Cover the pan with a tight fitting lid, and let the potatoes steam on low heat for about 15 minutes.
Remove from heat. Serve with roti or daal chawal.