Slice potatoes and 1/8 onion

Fry potatoes and onion in olive oil and salt until tender to the knife

Mix in a separate bowl eggs, cubed chorizo and rest of sliced onion

Add fried potatoes to the bowl, mix and add salt

Preheat a Teflon pan with olive oil

Pour mix in pan, even out to make a nice pie, cook at medium heat for 3-4 minutes

Flip pie, with the aid of a flat plate or tray, and cook for 3 minutes the other side in pan (taking care not to destroy the nice shape of the tortilla)

Serve