Heat butter in saucepan on high heat and then add celery.
Sauté for one minute, then lower heat and simmer for approx. 5 minutes until celery softens.
Raise heat to a medium heat and the add leaks and sauté until they soften.
Add parsley and sauté until wilted.
Add salt and pepper and sauté.
Add spinach in batches (approx. 6) sauté and allow to wilt before adding the next batch.
Once spinach has been added, pour in stock and gently mix until ingredients are completely combined.
Puree ingredients using a conventional blender, or if you have one, you can use a hand blender in the saucepan.
Once your ingredients are pureed, return to the saucepan and heat through.
Serve each bowl of soup with a drizzle of white truffle oil and a fruit or vegetable chip.