boil a pan of broccoli and/or cauliflower until softened, then remove with a spoon, keeping the water
add the macaroni to the same water (add more if needed), salt it, and boil until softened, then drain
put 60g butter in an empty pan and melt on low heat
gradually mix in 50g plain flour, stirring until it forms a smooth paste
slowly add 500ml milk, pouring a little at a time and stirring continuously until smooth and thickened
increase the heat slightly, then gradually mix in 1/2 bag of lighter cheese and 1/2 bag of mature cheddar or similar, stirring until melted into a smooth sauce
add the macaroni and broccoli/cauliflower and stir until everything is evenly coated
serve with crispy fried onion pieces if ya want :3