Heat your oven to 180°C. Chop your cauliflower into florets and roughly chop the leaves and stems if they are looking good. Add the cauliflower to a baking tray and drizzle with half of the olive oil, salt and pepper. Put in the oven to roast for 10 mins. After 10 mins, add the gnocchi and give everything a toss, then return to the oven for another 10 mins.

While everything is roasting, melt butter in a saucepan over a medium heat. Add your flour, then mix to a paste and cook for another 2 mins. Gradually pour in your milk in small increments, whisking constantly so you have a smooth paste before pouring the rest in. Once all the milk has been added, bring your mixture to a boil and let it simmer for 2 mins until thickened. Remove your sauce from the heat. Add your mustard and the cheddar and mozzarella, stirring until melted. Season to taste with salt and pepper.

Preheat a grill to medium. Tip your cauliflower into a baking dish, pour over the cheese sauce and grate over the Parmesan. Grill until golden and bubbly, then remove from the oven before scattering with parsley.