Cook the pasta as directed on the packet, preferably leaving it slightly undercooked. Drain well.
Heat a large, non-stick pan. Add the oil followed by the cumin seeds, mustard seeds and onions. Cook until onions light brown.
Add the garlic, chillies and mushrooms and continue to cook for another 2 minutes.
Add the tomatoes, bring to the boil.
Add the garam masala and reduce the heat and simmer for 5 minutes.
Stir in the pasta. Garnish with coriander and serve hot.