Heat the butter in large pan over a medium heat, add the shallots, gently sauté for 2 minutes. Add garlic and sauté for further 1 minute.
Add the stock and feta and cashew nuts.
Bring to boil then add the chopped courgettes. Bring back to the boil and simmer over medium heat for a further 4-8 minutes or until the courgettes are just softened yet still green. Lightly season with sea salt and white pepper.
Remove from the heat and using a handheld blender, mix into a smooth consistency. Add the butter to the soup.
Check seasoning and adjust as required. Keep warm.
Serve immediately with a sprinkle of seed and nuts toasted.