Heat olive oil in a large cast iron skillet over medium heat. Add garlic and onion, and cook, stirring frequently, until onions have become translucent, about 2-3 minutes.
Stir in rice until toasted, about 2 minutes.
Stir in tomato sauce and vegetable broth, and bring to a simmer, about 2 minutes.
Stir in corn, carrots, peas, chili powder and cumin; season with salt and pepper, to taste. Bring to a boil; cover, reduce heat and simmer until rice is cooked through, about 13-16 minutes.
Stir in tomatoes until heated through, about 1-2 minutes.
Serve immediately, garnished with cilantro, if desired.
Notes
Rinse the rice prior to using. Using a fine mesh strainer, rinse the rice under cold water to remove any excess starch. Dry thoroughly as wet rice will steam.
Toast the rice. Toasting the rice beforehand will add a nutty richness to the rice. Watch out for burnt grains.
Make it vegetarian. Vegetable broth can be used for the chicken broth.
No peeking. Let the rice cook undisturbed for 13-16 minutes with a tight-fitting lid. Once the lid is lifted, vital steam escapes, resulting in unevenly cooked rice.
Gently fluff. Fluff the rice using a fork to gently separate the grains without breaking them, never stirring. Stirring will lead to mushy rice.