Wash and chop the cauliflower florets to bite-size chunks and dry; I like to prepare these either the night before or in the morning and then leave them in a bowl to dry so that when roasting they get a bit of crust, rather than ‘steam’ because of the water. Once the pieces are sufficiently dry, mix them in a bowl with the olive oil, salt and cracked black pepper, lay them on a baking tray, and cook for 35-45 minutes in a Fan oven preheated to 180 degrees celsius, until cooked and nicely roasted.
In a large pan, about 15 minutes before the cauliflower is ready, spray the cooking spray, and, once warm, add the onion. Keep the flame to low and allow the onion to sweat, without browning for about 2 minutes, then add the stock cube and break in the pan, nicely coating the onions. Reduce flame to low.
Warm-up 1700ml water in a kettle and add to the onion and stock base, then leave it to simmer until the cauliflower is ready.
Once the cauliflower is ready and out of the oven, keep some pieces aside (I keep the smaller, crunchier bits on the side to add to each plate for decoration and extra texture), and add the rest to the water pot and continue simmering for about 10 minutes.
Switch off the gas and let the chunky soup cool down until it is safe to blend.
Before blending add the lemon juice and nutmeg to the soup, check for salt and adjust, blend and bring back to the boil.
Serve with sprinkled chopped spring onion and roasted cauliflower on top.