Heat oil in a cooking pot and add chopped onions. When the onions are about to turn golden, add cumin seeds and mustard seeds and fry until the onions are golden.
Add tomatoes, stir fry for a minute.
Add Salt, red chili powder, turmeric powder, garam masala powder and coriander powder. Stir fry for a minute.
Now add a little water (4-5 tbsp), cover and allow to cook on low flame until the tomatoes are mushy and the oil leaves the gravy.
Now add potatoes and stir fry for 2 minutes.
Add chopped beans and green chilies. Cover and cook for 10-12 minutes or until the beans and potatoes are cooked.
Remove the lid and sprinkle 1/2 tsp garam masala and some fresh chopped coriander.
Aloo Beans curry is ready. Serve with roti or naan. Enjoy!