1
Bring water to a boil and add the broken-up macaroni, elbows, and salt. Cook uncovered until tender but not overcooked (about 8 minutes).
2
Preheat a moderately hot oven to 350F, 180C, or Gas Mark 4.
3
Drain the macaroni thoroughly, put it back into the same hot saucepan cooked in, and mix in the butter.
4
Grate the cheese and mix it with the macaroni while it is still warm.
5
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.
6
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.