Ok Charlie, here's my recipe:
Allen’s Mexican Rice
Yields: about 3 c
2 T vegetable oil
½ c chopped onions
½ c chopped green bell peppers
2 T frozen peas, optional
2 T frozen corn, optional
1 t minced garlic
1 T Mexican Seasoning Mix
1 t cumin
½ t chili powder
½ t oregano
One 8 oz can tomato sauce
1 ½ c rice
2 c chicken stock
2 t salt, or to taste
In a saucepan, heat the oil. Add the onions, bell peppers, garlic, and if you desire, the peas and corn. Season with the Mexican Seasoning Mix, cumin, chili powder, and oregano. Sauté over medium heat until the onions are soft and beginning to become translucent. Add the rice and sauté until the rice is toasty. Add the tomato sauce and stir until it’s fairly well blended. Increase the heat to medium-high and cook this mixture until the tomato sauce mixture begins to caramelize a bit. Add the chicken stock and bring to a boil. Stir to make sure everything is mixed well. Check the seasoning and add more salt if needed. Bring to a boil, cover, reduce heat to a simmer, and cook for 18 minutes. When done, fluff with a fork and serve.
Mexican Seasoning Mix
¼ c chili powder
¼ c cumin
¼ c ground coriander
¼ c granulated garlic
1/8 c ground black pepper
1/8 c red pepper flakes
1 T salt
Blend together and store in an airtight container.
The basic recipe yields about six servings of 1/2 c each. For 100 people, you'll need to multiply everything by 16.6666666667. You'll probably need to bump the Mexican Seasoning mix a couple times, at least.
When it comes to cooking it, if the kitchen you're going to be using has a tilt skillet, use that. It's a HUGE skillet that can hold an extremely large quantity of food. Mexican Rice for 100 won't be a problem.
If you don't have access to a tilt skillet, just saute everything in the largest pan you can get. You may have to split this up into two or more batches, cooking all at once. When you get to the point where you're ready to add the liquid, take rice/vegetable mixture and divide it evenly between some 4" hotel pans (ask the cooks or chef for them, they'll know what they are). Deglaze the pans with the stock, and bring the liquid up to a boil, and CAREFULLY divide that evenly between the hotel pans. Cover those hotel pans with foil, and place them into a 350°F for 25 - 30 minutes.
If you have the time, see if the chef or food purchasing agent for the kitchen can get you some boxes of Sysco Mexican rice. This is a pre-boxed mix that's pretty good. I'm not sure how many people one box will feed.
Hopefully this helps.