Heat the oven to 200C/180C fan/gas 6. Spread the baguette (or leftover bread) chunks over a baking sheet, drizzle with the melted butter and season. Bake for 6 mins until crisp, then set aside.
Boil the pasta for 2 mins less than stated on the pack, then drain.
Add the Colman’s Cheese Sauce mix into a pan, then add the milk as per back of pack. Sprinkle in the Mustard Powder. Take off the heat, then stir in the cheddar and parmesan.
Stir the pasta into the cheesy sauce, and season with salt and pepper. Tip into a large ovenproof dish, or four individual dishes.
Scatter over the bread and the remaining parmesan, then bake for 20 mins until crisp and golden.
Using damp, clean hands take a piece of chilled Macaroni Cheese, roughly the size of a golf ball, and put on a tray. Repeat with the remaining Macaroni Cheese.
Dip the arancini first into the seasoned flour, then in the beaten egg and then the breadcrumbs, so they’re well coated.
Fill a pan no more than 1/3 full with vegetable oil and heat to 180C or until a cube of bread browns in 30 seconds. Cook the arancini, in batches, for 2-3 minutes or until really crisp and golden, then drain on kitchen paper and season lightly with sea salt flakes.