Chop the onion and seed and chop the tomatoes. Blend onion, tomato and garlic together in a large blender. In a heavy skillet, fry the rice in the oil until golden brown. The rice browns fast when it browns, but stays white a long while. Do not overbrown.
When rice is brown, quickly pour the tomato mixture into the rice. Stir together with the rice, frying until the juice is absorbed. When the rice has turned red and seems dry, add the chicken broth. Add the frozen vegetables and place the chiles on top of the rice. Cook on low heat approx. 20 minutes until the top is bubbly and most liquid is gone. Cover with a cloth or clean towel and place a cover over the pan. Allow to steam for 10 minutes longer with the heat off. Remove the towel and cover. Stir and serve. To reheat, return to pan, sprinkle with water and reheat on low.