In a large skillet, heat the oil over medium heat until hot but not smoking. Add the onion and garlic and cook for 1 minute. Add the rice and cook, stirring occasionally, until the rice is golden brown, 6 to 8 minutes; lower the heat if necessary to keep rice from buring. Stir cumin and cook for 30 seconds. Stir in the chicken broth, tomato sauce, salt and pepper.
Bring to a gentle boil, reduce the heat, cover the pan and simmer until most of the liquid is absorbed and the rice is cooked, about 30 minutes. Uncover the pan a few times during cooking to check the liquid. Add more chicken broth if the rice starts to burn and sticks to the bottom of the pan. Do not stir during cooking; it causes the rice to break down and become sticky.