Place a large stockpot over medium heat. Sprinkle the bottom with a pinch of salt and heat for 1 minute. Add the oil and heat for 30 seconds, being careful not to let it smoke. This will create a nonstick effect.

Add the celery root, celery, and onion and sauté for 6 to 10 minutes, stirring often, until soft but not brown. Add the stock and bay leaf, bring to a boil, then reduce the heat and simmer for 30 minutes. Add the Cashew Cream and simmer for an additional 10 minutes.

Working in batches, pour the soup into a blender, cover the lid with a towel (the hot liquid tends to erupt), and blend on high. Season with salt and pepper to taste. Ladle into bowls. Place a spoonful of the diced apple in the center of each serving, drizzle the Chive Oil around the apple, and serve.