Sauté onion and celery in butter and oil until onion is translucent.
Add flour and whisk over medium heat for 3-5 minutes.
Add the half & half and chicken stock and stir well.
Add the chopped broccoli and cook over low heat 20-25 minutes.
With an immersion blender, blend the broccoli until it's the consistency you like.
Add salt and pepper and nutmeg.
Return to heat and stir in cheese, heat until melted and garnish with a little shredded cheese.
Serve with crusty bread!