Cut some very small florets of cauliflower and broccoli and set aside to use as crunchy croutons later on.
Peel and slice the onion and crush the garlic. Heat the oil in a large, lidded saucepan and gently fry the onion and garlic until soft.
Meanwhile, chop the remaining broccoli and cauliflower - it doesn't need to be in neat florets, just chop into fairly small pieces. You can use most of the stalk of the broccoli too - just trim off the end and finely slice the stalk.
When the onion is soft, add the broccoli and cauliflower to the pan. Pour in the vegetable stock, and bring to the boil. Season well with salt and black pepper.
Reduce to a gentle simmer and cover with a lid. Cook for 12-14 minutes until the broccoli and cauliflower are soft.
Remove from the heat then use a hand blender to blitz to a smooth purée. Add the vegan cream and parsley (leaves only, not the stalks) and blitz again. Taste and adjust seasoning if required.
In a small frying pan, heat a little olive oil and gently fry the small broccoli and cauliflower florets you set aside. Cook for 5-7 minutes - they should be nutty and firm but cooked through. Sprinkle with salt and divide between the bowls of soup as a garnish. Serve immediately.
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Notes
You may need to adjust the amount of vegetable stock. As cauliflowers and broccoli come in such varying sizes, your soup may need more or less stock to create a thick and creamy consistency. The quantities below are based on a fairly large cauliflower and broccoli.Blitz your soup for longer than you think to get a really silky smooth consistency. It is tempting to stop blending as soon as all the lumps have disappeared, but if you keep going for another minute or two it makes such a difference to the finished soup.