How to Make It
Par boil the potatoes with the carrot, parsnips or swede for 10 minutes then drain them and leave to cool.
Coarsely grate the par-cooked vegetables into a large bowl and stir in the grated courgettes, most of the spring onions, and egg.
Lightly oil a frying pan and cook the rosti mixture in small flat fritters until crisp and golden on both sides. Flatten with a fish slice as they cook. They will need to be about 3-4 minutes on each side. Serve on a plate and scatter the remaining spring onion on top.