Finding a good vegetarian Mexican rice recipe has been a challenge during my eight-year serious cooking run. Most recipes seem to result in incredibly bland or salty dishes, and none generally taste as good as one can find at a restaurant (which should lead me to doubt what exactly they put in the "vegetarian" rice when I am out...).
For some reason though (sadly, I don't remember why!), I decided to shelve my pessimism recently and tried the Cooks Illustrated Mexican Rice recipe. The first time I made the recipe, I halved the amount of rice but kept a whole onion and two small tomatoes for it. The result was amazing - flavorful and also moist and yet not mushy. It was also very easy to make because most of the cooking occurs in a dutch oven placed in the oven instead of taking up space on the stove top.
The second time I made the recipe, I made the full recipe portion but ended up with slightly less than the tomato/onion liquid called for in the recipe by using one onion and two tomatoes. The result the second time was more bland, though it was still good. The next time I make the recipe, I will probably use 3 - 4 tomatoes and 1.5 onions because I don't think it will overpower the dish.
The bottom line is that this is an excellent vegetarian Mexican rice recipe that can be a quick side dish to add to any meal - particularly because while the rice cooks in the oven, one has the whole stovetop set available for preparing other meal elements (beans, tortillas, etc.).