Heat 1 tbsp olive oil in a non stick pan. Add quarter of the grated potato and spread into a fairly thick and even layer. Sprinkle a little salt and let it cook on low heat. Chop onion, tomato and spring onion greens.
Drizzle a little olive oil over the potatoes and when the underside is lightly browned, flip it over carefully and cook. Place a quarter of the onion-tomato mixture in the centre and sprinkle a quarter of the cheese over. When the cheese begins to melt, fold one side over the topping and cook till golden.
Make more omelettes similarly. Serve hot immediately.