Bring water to a boil and add the broken-up macaroni, elbows, and salt. Cook uncovered until tender but not overcooked (about 8 minutes).

Preheat a moderately hot oven to 350F, 180C, or Gas Mark 4.

Drain the macaroni thoroughly, put it back into the same hot saucepan cooked in, and mix in the butter.

Grate the cheese and mix it with the macaroni while it is still warm.

Whisk the egg until fluffy, and add the milk, onion powder, white pepper, salt, pepper sauce, and mustard. Pour in with the macaroni and mix.

Place in a greased ovenproof casserole dish. Top with butter, some grated cheese, and fine breadcrumbs. Bake in the center of the oven for about 30-45 minutes, depending on the dish’s depth.