Peel and finely chop the onion. Peel and finely chop the carrots. Peel and roughly chop the parsnips. Warm a pan for 1 min. Add 1 tbsp oil and the chopped veg. Season. Stir and fry for 8 mins till they start to soften.
Halve the chilli and flick out any seeds. Finely chop it. Stir the chilli into the veg. Crumble in the stock cube. Pour in 800ml boiling water (or use hot homemade stock). Cover. Turn up the heat and bring to the boil. Simmer for 15 mins till the veg are soft.
Meanwhile, tip the sunflower seeds into a dry frying pan. Toast over a medium heat, shaking the pan now and then, till the sunflower seeds are golden. Tip into a bowl.
When the veg are soft, tip half the sunflower seeds into the pan. Ladle into a blender and blitz till smooth, or use a hand-held blender in the pan. Taste and add more salt and pepper if you think it needs it. Ladle into warm bowls. Top with the remaining sunflower seeds and some parsley leaves to serve.