Boil macaroni in sufficient water till 'al-dente' (cooked but not too soft). Drain and refresh under running water. Drain and set aside.
Heat butter in a pan. Add maida and sauté lightly, taking care that it does not change colour.
Add milk gradually, stirring continuously so that no lumps are formed.
Add grated cheese and keep stirring. After adding cheese the sauce will thicken further, so add more milk to adjust the consistency.
Add salt and white pepper powder and mix.
Heat some butter in another pan. Add macaroni. Toss. Strain the sauce into this pan and mix gently.
Add some more cheese. At this stage if you want to bake the dish you can do so till the cheese at the top becomes a light golden.
Garnish with parsley and serve hot.