Prepare the couscous
Heat the butter in a pan, sauté the onion. Add the beetroot cubes, stock and juice, bring to the boil. Add the couscous, remove the pan from the hob, cover and allow to stand for approx. 10 mins., loosen with a fork, season.
Poach the eggs
Bring the water and vinegar to the boil, reduce the heat. Crack the eggs one at a time and carefully slide into the simmering water, cook for approx. 4 mins. Remove, drain, serve on top of the couscous, scatter over the purslane and pomegranate seeds.