Method

Add onion & butter in a saucepan over a med heat & cook until soft but not coloured, add the flour & pepper stir in then cook for 1 minute.

Stir in the milk, water & stock cube, then simmer for 5 mins giving the soup base a stir occasionally.

Have a stick/hand blender of a liquidiser at the ready, add the watercress to the pan & cook for no more than a minute, take of the heat then blitz smooth, add cream stir in & serve into bowls & garnish.