Heat the olive in a medium skillet on medium heat. Add the potatoes and fry stirring regularly for 15 minutes.
Add the chorizo and continue to fry for a further 10 minutes.
Add the spring onion, vinegar and rosemary then stir to mix and season with salt and pepper.
Make 5 wells in the hash and crack an egg into each. Sprinkle over the parmesan and fry until eggs are cooked to your liking. Serve immediately.