Bring plenty of water to the boil and salt generously. Boil your pasta 2 minutes short of the time stated on the package.
While the pasta is boiling, scald milk in a small pot and add the garlic granules, if using, all the cheese and the butter. Turn off heat and just allow the cheese to sit there and melt while your pasta is cooking. When pasta is nearly done, whisk melted cheese into milk to blend.
Drain cooked pasta and immediately return to pot. Add hot milk/cheese mixture and stir pasta to coat. Cover pasta and allow to sit in this mixture for 10 minutes. Stir again to coat (most of sauce will have been absorbed by the pasta, leaving a thick, creamy sauce in the pot) and serve.