Watercress Bisque - cooking recipe

Ingredients

2 bunches watercress (about 300g weight)
50 g butter
4 medium potatoes, peeled and chopped
2 medium onions, peeled and chopped
1/4 teaspoon salt
1 1/4 liters vegetable stock or 1 1/4 liters chicken stock
300 g cream
3/4 cup ground almonds
1 -2 teaspoon lemon juice (to taste)
1/2 - 1 teaspoon salt, extra (to taste)
1 pinch white pepper (or to taste)

Preparation

Chop off and discard the lower third of the bunches of watercress.
Pick through the watercress, discarding any obviously woody stems.
Chop watercress roughly, and, if desired, reserve some sprigs for garnish.
Melt butter in a large saucepan over a medium heat.
Add potatoes, onions and watercress and stir well until vegetables are well coated in the butter.
Sprinkle vegetables lightly with salt.
Reduce heat to very low and cover vegetables with a piece of baking paper, foil or similar, tucking it in at the edges.
Sweat the vegetables over a very low heat for about 20 minutes, stirring and then re-covering, about half way through.
Add stock, increase heat and bring to a gentle boil.
Decrease heat and simmer for 15 minutes.
Puree in batches in a blender or food processor.
(The stems may prove a problem for a stick mixer).
Return soup to pan and add cream and ground almonds and lemon juice, white pepper and salt to taste.
Reheat to serve.
Serve garnished with sprigs of watercress OR float a young nasturtium leaf and flower on the top of each bowl.