Rough sort of recipe - I tend to wing it without very accurate measurements of things:

Serves 4 adults.

• Cook 500g of macaroni or other appropriate pasta shape to al dente (I generally go about 2 minutes under the recommended packet instructions)

• Fry up 150g of well-diced chorizo and reserve.
• Melt 125g of butter in the same pan (there should be some oil left from the chorizo)
• Chuck in some flour (I guess about half a cup) and stir to a roux which is roughly the consistency of wet sand
• Stir until not lumpy
• Add some minced garlic, a level teaspoon of English mustard powder, a pinch of nutmeg, a bay leaf, stir and then immediately start adding the milk to bring the temp down a bit and make sure the garlic doesn't burn in the roux/napalm.
• Total of about 2 1/2 pints of whole-fat milk. You have to add it in dribbles to start with and stir vigorously. The roux will glump up into a claggy mess at first but gradually combine with the milk. Once it's a reasonable consistency you can pour in the rest of the milk.
• Bring the milk to about 85-90'C (185-195'F) then stir in some grated cheese. I used a mix of Emental, Extra Mature Cheddar, and Monterey Jack.
• Season with black pepper

• Once that's all thick and cheesy and gooey and nice, return the chorizo to the sauce, then stir in the cooked pasta.
• Pour the cheesy pasta into an oven-safe dish or pot, sprinkle breadcrumbs over the top and bake for 20 minutes at 180'C / 360'F.
• Check it's bubbling nicely under its breadcrumb hat then grill for 5 minutes to get those breadcrumbs golden.

• Let it cool for 5 minutes while whipping up a simple green salad.

  I like it with some OG Tabasco to taste.