Put the potato, onion and halloumi in a bowl and add the flour, a pinch of salt and pepper and a tablespoon of oil and mix well.
Heat ½ tablespoon oil in a small 20cm frying pan over a medium heat. Add a quarter the potato mixture and press to spread out to the edges of the pan. Cook for 3 minutes, flip out onto a plate and return to the frying pan to cook the other side for another 3 minutes. Repeat 3 times with the rest of the mixture.
Place the potato cakes on plates and fry the eggs according to your liking. Top each with a swirl of yoghurt, add a handful of watercress and a drizzle of chilli oil. Top with the fried eggs and serve.
Nutrition information is an estimate and will vary depending on the exact ingredients used.