1. Cut the broccoli stalks into rough chunks and cook until tender, either by steaming or microwave on High along with a couple of tablespoons of water.
2. Using either a hand blender or liquidiser, blitz the broccoli for a few seconds. Add the cremé fraiche, lemon zest, thyme and chilli, if using and blitz again until smooth. Decant into a serving dish and chill before serving.
Hint: The hand blender or liquidiser will give a finer consistency than by using a food processor.