You can add just about anything you want to basic risotto: prosciutto, vegetables such as peas, seafood such as shrimp, or herbs and other seasonings such as saffron. (The recipe that follows is for one of my favorite variations of the basic risotto, with wild mushrooms and peas.) But you usually don’t want these ingredients to cook for 30 minutes with the rice, or they’d become overcooked—tough, dry, and flavorless. So instead of cooking these other ingredients with your rice, cook them separately.
To save dirtying another pan, you can cook the other ingredients before you start with the basic risotto recipe, in the same pan that you’ll use for the rice.
On the other hand, to save time, you can use another pan, and cook them while you’re making the risotto.