Heat butter in a non stick kadai. Add cumin seeds and allow it to splutter.
Add onions and saute till brown. Add coriander powder, turmeric powder and red chilli powder. Mix well.
Add little water and cook for three minutes.
Add tomatoes and capsicum and saute well for two minutes.
Add potatoes, pasta and salt. Toss well.
Finish with chopped coriander leaves and serve hot.