Heat butter in a medium sized saucepan over a medium heat.
Sauté onion until softened, about 2-3 minutes and add the pasta. Stir to coat well.
Add the vegetable stock, stir and pop the lid on the pan. Cook for 10 minutes, stirring occasionally to keep the pasta from sticking to the bottom of the pan.
When the stock is completely absorbed and the pasta is al dente (it still has some bite to it) stir in the cheese, salt, pepper and parsley.
Serve immediately.
Notes
Serve with peppered pork grills or minted lamb chops.