Heat oil in a medium saucepan over medium heat. Add onion and cook, stirring, until softened, 2 to 3 minutes. Add rice and cook, stirring, for 1 minute. Add broth and bring to a boil. Cover tightly and reduce heat to low. Cook until rice is tender and water is absorbed, 15 to 20 minutes. (Don't peek.) Fluff with a fork, cover and let stand for 5 minutes.