Heat the rapeseed oil in a small non stick frying pan on a low heat. Crack in the egg, season the white with a little sea salt and cook very gently until the white has just set then transfer to serving plates and keep warm in a very low oven until the rest of the eggs are cooked. Do the same with the rest of the eggs (in a couple of pans at a time preferably) and keep them warm on plates in a very low oven.
Meanwhile melt the butter in another pan and heat the vegetables and parsley and season to taste. Scatter the vegetables and butter over the eggs and serve immediately.