Bring a pot of salted water to the boil, and cook the long macaroni (broken to fit in the pot as necessary). Cook the pasta to al dente, about 8 minutes.
Pre-heat oven to 180 C, a bit less for a fan oven.
Drain macaroni thoroughly, and put back in the hot saucepan, add the butter.
Add the grated cheese to the macaroni, in the warm pot, and mix as you add.
Whisk the egg until fluffy, add the milk, onion powder, white pepper, salt, pepper sauce, ketchup, and mustard.
Add the egg mixture to the macaroni, mixing as you go.
Place the mixture into a greased casserole dish. Top with a little butter, the 2 tbsp of grated cheddar, and the fine breadcrumbs.