Bring the stock to a boil in a medium saucepan. Cover and keep hot over low heat. Heat the remaining 1 tablespoon of olive oil in the large saucepan. Add the garlic and cook over moderate heat until fragrant, about 1 minute. Add the rice and cook, stirring, for 2 minutes. Add enough hot stock to cover the rice, about 1 1/2 cups, and stir constantly over moderate heat until the stock has been absorbed. Continue adding stock, about 1 1/2 cups at a time, and cook, stirring, until it has been completely absorbed before adding more. The rice is done when the grains are just tender and the sauce is creamy, about 20 minutes.