Saute the onion and garlic in the butter until softened over a medium heat. Add the florets and stir through the garlic/onion mixture for a few minutes.
Add the stock and milk and season with salt and pepper.
Bring the mixture to the boil and then let it simmer for 20-30 mins. (florets will be tender).
Using a handy stick blender, whizz everything up until you have a nice smooth consistency. Add the cream to achieve a lovely, extra smooth, velvety texture
Serve with a generous amount of grated Parmigiano Reggiano on top.