In a large pan fry the onion and garlic in the butter and oil till soft and lightly golden in colour. Cut the courgettes into chunks and add to the onion and stir fry for a minute or two.
Sprinkle over the nutmeg and season lightly with salt and black pepper.
Pour over the stock and bring to a boil and cook for 20 minutes or until the courgettes are tender. Process the soup till smooth in a food processor or use a stick blender. Add the cream and crumble in 2 discs of feta cheese. Bring to a simmer.