Place the rice in a 3- or 4-quart baking dish. Cover with very hot tap water and stir vigorously to clean and soften the rice. Drain the rice in a colander. Repeat twice with fresh hot water.
In a mixing bowl, combine the chicken base with 1 quart of very hot tap water. Mix well with a wire whisk.
Add the dissolved chicken base to the soaked rice, mix well, and place the rice in the oven uncovered for 15 minutes.
Remove the rice from the oven, add the melted butter, and mix thoroughly. Cover the dish and return it to the oven for 15 more minutes.
Meanwhile, combine the green and red bell peppers in a mixing bowl and cover them with very hot tap water. Set aside to soften.
When the rice has finished baking, drain and rinse the softened peppers. Add the peppers and cilantro to the rice, mix thoroughly, and serve.