Peel and chop parsnips, turnips, potato and carrots. Chop celery and dice onion.
Place parsnips, turnips and carrots on a sheet pan and drizzle with olive oil, salt and pepper. Cook at 400℉ until soft and caramelized.
In a Dutch oven, add olive oil, onions and celery. Cook until tender. Add in 4 cups of vegetable stock and potatoes and bring to a boil. Once potatoes are soft, add in the sheet pan vegetables. Remove from heat and mix together with immersion blender. Once combined, add in heavy whipping cream and salt and pepper to taste.