Heat the butter and olive oil in a large saucepan over a medium heat. Add the onion and cook gently for 5-10 minutes until softened. Stir in the garlic and cook for another minute.
Add the parsnips and apples, stirring well to coat everything in the buttery onion mixture.
Pour in the stock, bring to a gentle boil, then reduce the heat and simmer for 20-25 minutes, or until the parsnips are very tender.
Remove from the heat and blend until completely smooth using a stick blender or food processor.
Stir through the dairy-free milk, season well with salt and pepper, and gently reheat without boiling.
Serve warm with a slice of seed bread or some oatcakes and an extra crack of black pepper.