Preheat the oven to 350. Bring the broth up to a rapid boil. Place the brown rice in a casserole pan— 8×8 for the original recipe, plan on larger if you double it. As soon as the broth is boiling, pour over the brown rice and stir slightly. Cover tightly with foil or a lid. Place in the oven for 20 minutes. But, plan on 1 hour total of bake time.
This is a great time to start chopping your vegetables:
Thinly slice the onion.
Chop up the broccoli including any stems.
Thinly slice the mushrooms.
When 20 minutes are up, season the chicken with salt and pepper. Place half of the oil or butter in a skillet over medium heat and sear the chicken on one side to form a golden crust. Carefully (watch for steam!) open the casserole pan and add the chicken pieces with the golden side up. Seal it back up and continue to bake.
Add the remaining butter to the skillet and saute the onions until they get a bit of color over medium-high heat. Then saute the mushrooms until wilted. Add the broccoli and turn off the heat in the skillet.
Open the casserole pan again and toss in the vegetables and thyme. You will probably need about 10-15 more minutes of bake time after adding the veggies.
When an hour is up, carefully remove the foil and taste the rice. If it needs more time add a splash of hot water and continue to bake for 5-10 more minutes.
Serve the chicken with a scoop of the rice and veggies.