Slice the onions and roughly chop the celery. Heat a deep pan, add the oil and cook the onions and celery over a medium heat for 10 minutes until they are soft.
Chop the celeriac into chunks, peel, core, quarter the apples and add them to the pan. Pick in the thyme leaves making sure not to add the woody bits and add to the pan cook for 2 to 3 minutes.
Add the stock, season and simmer over a low heat for 30 to 35 minutes until the celeriac is tender. Remove from the heat and blitz with a stick blender until smooth. Stir in 2/3 of the creme fraiche
Spoon the soup into bowls and top with the remaining creme fraiche. Garnish the soup with the chorizo, dried apples and edible flowers and leaves, drizzle with the chilli oil and serve immediately.