Begin by bringing your chicken or vegetable stock to a simmer. Keep the liquid simmering while you prepare the risotto. Do not add cold stock to your risotto!
In a large sauce pan, heat olive oil over medium heat and sauté a small finely diced onion or shallot until tender. Stir in rice and cook, stirring, for a minute.
Pour in white wine and cook, stirring until it has evaporated, a minute or two. Stir in diced tomatoes.
Begin adding the simmering stock one ladle full at a time. Stir occasionally and when the liquid has been absorbed add another ladle full of stock. Continue this process until the stock is all used up and the rice is tender but still has some bite to it. This will take from 20-25 minutes.
When the rice is tender, remove the pan from heat and stir in a knob of butter (optional) and grated cheese. Garnish with freshly chopped basil and serve with extra grated cheese at the table.