Bring the stock to the boil, add the peas and cook for 2-3 minutes. Pull the mint leaves off the stalks, reserving a few as a garnish, then chop. Add to the peas then blitz in a processor until smooth.
Return to the pan, heat gently, season with black pepper to taste then pour into bowls. Cut the goat's cheese into thick slices and put into the soup. Garnish with whole mint leaves and serve.