Break the cauliflower into florets and put them into a saucepan.
Peel the parsnips and cut them into bite-sized pieces. Add them to the pan.
Add the stock cube, if using, then cover with water and bring to the boil. Reduce the heat and simmer for about 10 minutes, or until the vegetables are tender.
Drain well, then return the vegetables to the pan. Add a splash of milk and the cheese.
Using a stick blender or potato masher, mash the vegetables until smooth or slightly textured, depending on your preference. Add a little more milk if needed.
Taste and season with salt and freshly ground black pepper.
Fold in the fresh herbs and serve immediately.