Drizzle olive oil and onion bits in a relatively cold pan. Increase the heat slowly until the onion starts to cook. Fry about 5 minutes, stirring all the time. When the onion starts to turn nice and yellow, add the rice and sauté the whole thing for a minute.
Pour the wine over the rice. Toss gently until the wine is half absorbed.
Add the stock little by little and swirl until the rice thickens. The risotto must not dry out and stick to the bottom at any point.
When the rice is almost done (still hard at the core), add the parmesan or any other fillings you like.
Simmer for a while and swirl the risotto until juicy. Add more stock if needed. The idea is to get a runny consistency in the risotto. Italian risotto is never dry.