Place a small soup pan on a medium heat and add 1 small diced onion and fry in 1 tsp of olive oil for about 2 minutes until soft. Add 1 small peeled and roughly chopped potato and fry for another 1 minute. Add 500ml of boiling water with 1 vegetable stock cube and cook for around 10 minutes until the potato is completely soft. Meanwhile, in a separate pan of water, poach an egg so its slightly undercooked and leave to drain on the side. Add a handful of watercress and spinach to the soup pan and bring back to the boil for a maximum of 1 minute. Blend with soup until completely smooth add to a serving bowl. Place the poached egg in the soup bowl and finish with 1 tsp drizzle of crème fraiche. Serve with a wholemeal or granary bread roll.