Heat the oil in a saucepan over a medium heat. Add the onion and garlic and fry for 3–4 minutes, until softened.
Add the frozen peas and chicken or vegetable stock and bring to the boil. Reduce the heat and simmer for ten minutes.
Add the cream and use a hand blender to liquidise the soup.
Season, to taste and serve in a warm bowl, garnished with a mint leaf.