Heat a non stick frying pan over a medium heat and add 100g of the butter. When foaming crack in the eggs. Fry until crisp, then sprinkle with the parsley and chilli.
Meanwhile in another frying pan heat the remaining butter and, when foaming, add the spinach. Fry until it wilts and drain onto kitchen paper.
To serve spoon the spinach over the toasted sourdough and top with the eggs and their butter.