Coat the bottom of a medium sized sauce pot with cooking oil and place over medium heat. Add the onion, garlic and celery and sauté for 2 minutes. Add the chopped parsnips, apple, cream and water. Bring to a simmer and continue to cook until the parsnips are soft. Transfer the soup base to a blender and puree until smooth. Return to the pot and season with lemon juice, salt and pepper. Serve and enjoy!