Heat a dash of oil in a large pan or wok, and add the onion. Cook over a medium-low heat for 5 minutes, until soft and translucent, then add the garlic and mushrooms (or whatever vegetable you're using). Continue to cook for a further 5-10 minutes until the mushrooms have cooked right down.
Add the rice, and cook over a medium heat for a minute or two, mixing well to coat it in the oil.
Next, add about 250ml (1 cup) of the vegetable stock. Mix well, and allow to simmer gently for a few minutes until most of the excess liquid has been absorbed. Add the remaining stock about a cup at a time, allowing it to be absorbed each time before adding more (you can use a little less or more than the recipe states, if needed). Stir the risotto regularly to help it become nice and creamy.
When the rice is cooked to your liking (after around 30 minutes or so), add the chopped spinach, parsley, and grated cheese. Mix well, stirring until the spinach has wilted and the cheese has melted, then serve.