Melt butter in a thick bottomed pan on medium heat. Add oil so that the butter does not burn. Add onion, garlic celery and sauté till onions turn translucent. Add broccoli florets and cook for around two to three minutes.
Add vegetable stock, bring it to boil and cook for five minutes on high heat without covering the pan. Strain and cool the broccoli. Keep aside the stock. Blend the broccoli in a mixer. Mix it with the strained stock in a pan.
Put the pan back on high heat, bring to a boil and season with salt and white pepper powder. Add fresh cream, simmer for two to three minutes and serve hot garnished with sliced hazelnuts.