Macaroni and Cheese

Name: Macaroni and Cheese
Prep time: 15 min
Cook time: 50 min
Total time: 1 h 5 min
Cuisine: European, American, British
Ingredients: 60g butter; 5 slices cooked streaky bacon, crumbled; 150g crushed potato crisps; 450g cavatappi pasta, cooked al dente; 300g shredded Cheddar; Dash Worcestershire sauce; Dash hot sauce; Dash salt and freshly ground black pepper; 1/4 teaspoon cayenne pepper; 1/4 teaspoon freshly grated nutmeg; 1 teaspoon dry mustard; 1L milk, warm; 110g plain flour; 50g freshly grated Parmesan, for topping