Soup this good shouldn’t be this easy, but it is! And of course it's also brilliant for a vegan, egg-free, dairy-free or gluten-free wedding. The wasabi foam adds an impressive final touch.
For the soup
1litre vegetable stock (see my separate recipe)
salt to taste
For the wasabi foam
2tbsp olive oil
150ml soya milk
2tsp wasabi powder
Wash the watercress and remove the leaves. Heat roughly half the stock in a pan with the watercress – after about 10 minutes and when it is simmering, remove from the heat and allow to cool for about 10 minutes. Take a stick blender (or pour into a liquidiser/food processor) and blend the mixture until all the watercress has been chopped into fine pieces and you have a deliciously dark liquid. Pour back into the pan with the remaining stock and heat until nearly boiling. Season to taste with salt.
For the wasabi foam, place the oil and cornflour in a heavy bottomed pan and stir together while heating gently. Gradually whisk in the soya milk. Keep whisking until the mixture begins to boil, and then add the wasabi powder. You should end up with a spicy, foamy, creamy mixture, which should then be drizzled into the centre of each bowl of soup to serve.