Easy broccoli soup
Heat the butter in a saucepan and gently fry the onion until softened but not coloured.
Add the broccoli and stock, bring to the boil and boil rapidly for 3-4 minutes, or until the broccoli is just tender.
Season with salt and freshly ground black pepper and blend the soup using a hand blender until smooth.
To serve, pour the soup into a bowl and top with a dollop of yoghurt.