Place potatoes in a large pot of cold water, bring to a boil and cook for 10- 15 minutes or until tender. Drain and return to hot pan, allowing steam to escape.
Heat butter and oil in a medium frying pan over MED- HIGH heat. Once the butter is, melted and foaming add onions and cook for 5 minutes, only stirring occasionally, until onions start to turn golden and crisp. Add cumin seeds, ginger and garlic and continue cooking for a minute, then stir through the curry powder and cook stirring for a further minute. Remove from stove and set aside.
Mash cooked potato with milk until smooth. Reserve a quarter of a cup of the onion mixture, and fold remaining onion mixture through the potato. Season to taste with salt and serve topped with reserved fried onion and coriander.
Recipe Tip
Top any pie filling with the left-over fried onion & curry mashed potato. Followed by a pastry top or just a sprinkle of cheese.