Heat the oil in a large pan and cook the onion and garlic over a medium heat for 3-4 minutes until softened, stirring occasionally. Tip in the potatoes, carrots and parsnips, turn up the heat and cook for 6-7 minutes, stirring, until the vegetables are golden.

Stir in the curry paste or powder, pour in the stock and then bring to the boil. Reduce the heat, add the lentils, cover and simmer for 15-20 minutes until the lentils and vegetables are tender and the sauce has thickened.