Bring a pan of unsalted water to the boil, Remove all the leaves from the outside of the sprouts and place them in the water, lid on, turn down the heat and cook until parboiled – about 4-6 minutes.
Drain, then tip into the food processor, along with the cream, salt and pepper. Blend for 20 seconds or so – they should be roughly chopped up, not a smooth purée.
Stir all the parmesan into the sprout mash except for enough to sprinkle over the top, then transfer to an ovenproof dish.
Sprinkle the left over parmesan on top and bake for 8-10 minutes on HI until the top has developed a fine, crunchy crust.