In a large skillet, combine the rice and chicken broth. Bring to a boil over high heat. Reduce heat to a low simmer and cover. Simmer for 18-20 minutes, or until rice is cooked. Fluff with a fork and set aside, covered, to keep warm.
Melt the butter in the hot skillet over medium-high heat. Add the chopped onion and sauté until translucent and lightly browned (about 2 minutes).
Add the minced garlic, and sauté for about 30 seconds. Add the diced tomatoes and spices, and stir. Bring to a boil, then cover and reduce to a simmer on medium-low heat for 10 minutes.
Add the cooked rice to the tomato mixture and stir well to combine. Turn off the heat and cover to keep warm. Garnish with fresh cilantro, if desired, before serving.
Notes
Serve this delicious Spanish rice with your favorite Mexican dishes, or enjoy it as a satisfying side on its own.