Bring a pot of water to the boil. Add five pinches of salt then drop in the Brussels sprouts and cook until they are tender. Immediately drop them into a bowl of iced water to stop the cooking process. Strain and set aside while you work on the Mornay sauce.

Pre-heat an oven to 180 degrees Celsius/gas 4. Place the milk and cream in a small pot, bring up to the boil and then switch off the heat.

Heat another pot and add the butter, followed by the onion and bacon. Season with salt and pepper and sweat it down until the onion softens and the bacon is cooked.

Break up the chicken stock cube and mix it in, followed by the flour. Cook on a low heat for five minutes while continuously mixing. Pour in the hot cream and milk, as well as the cheeses, and whisk until it thickens.

Add the blanched sprouts and fold them through the sauce slowly. Pour the mixture into a small casserole dish.

Mix the breadcrumbs, truffle oil, Parmesan and parsley together in a bowl then sprinkle evenly over the sprouts. Place in the oven to bake for 12-15 minutes, until golden.