The capers are important in this dish as they take the place of the classic anchovies. Try those packed in salt rather than immersed in brine, as their flavour is far superior.
Preheat the oven to 190°C/375°F/gas mark 5. Bring a small pan of water, with a few drops of white wine vinegar, to the boil and carefully crack the eggs into the water. Poach gently for 1 minute only and then drain through a sieve.