Watercress Miso Soup

Yes, it can be so simple and yet delicious. Add udon or rice vermicelli to this, you have a bowl of noodle soup.
Preparation:     8 mins, Cooking time:  8 mins  
Ingredients (serves 2)
°         100g watercress
°         500ml water
°         1 slice ginger
°         Miso to taste
°         Some sesame seeds or chilli flakes or wolfberries, for garnish
1.      Place the ginger and water in a pot and bring to a boil.
2.      Add in watercresss and season to taste with miso.
3.      Ladle the soup into individual serving bowls and garnish with sesame seeds or chilli flakes or wolfberries.
4.      Serve immediately.