In a saucepan, heat up chicken or vegetable stock. It must be almost boiling by the time you start cooking the rice.
While your stock is heating, finely chop onions and garlic. Melt half of the butter with the oil in a large saucepan, then add the onion. Simmer for a few minutes. The onion shouldn't be browned, only get a nice translucent color. Add garlic and simmer for another half a minute.
Add the rice. Stir it thoroughly, the grains should be covered with the oil/butter/onion mix. Sauté the rice on medium heat for 2-3 minutes, the grains should have a transparent edge while still white in the middle.
Add your wine and stir it once. Cook on medium heat, let the liquids evaporate.
The rice should be cooked on medium low-medium heat, and the stock kept close to boiling temperature, otherwise it cools off the rice. Cooking requires your full attention, the steps described below have to be repeated until the rice is done. The exact cooking time for the rice is indicated on the package, usually 16-18 minutes.
Pour 1 – 1 1/2 ladle (that is 1/3-1/2 cup or 100-150 ml) of the hot stock on the rice.
With a wooden spoon or spatula stir the rice so that the liquid covers the rice evenly. Let the rice cook for a minute, stirring occasionally. The very essence of real Italian risotto is adding the stock little by little then let it evaporate. Usually it takes 1 - 1 1/2 minute to evaporate the stock depending on the size of your saucepan and the heat. When all the liquids have evaporated, start the process all over again by pouring some hot stock on the rice.
Between two steps grate the Parmesan and cut up the other ingredients of your choice: vegetables, mushroom, sausage etc.
About two minutes before the rice is ready, add your other ingredients to the risotto. Stir and add a little more broth. The result should be creamy and saucy, resembling to a rich, dense and somewhat overcooked soup. To get an idea, check out my last picture: rice in a creamy, thick sauce with porcini mushrooms.
Before done, add grated Parmesan and stir. Cook for about half a minute, then take off the heat. According to the Italians, rice has to be al dente, just like pasta. It should not be overcooked. Add the remaining butter and cover it. Let it stand for 2 minutes, until the butter melts. If it's too thick just add some more stock.