1: In a saucepan gently cook the onions and garlic in 1cm of water.
2: Once the onions are soft, add the potato and vegetable stock, then simmer for 5 minutes until the potato is just cooked.
3: Scatter in the peas and watercress, stir, cover, then simmer for 3 minutes.
4: Add the mint and blitz with a hand blender until smooth.
Photo credit: Patricia Niven
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