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