3-4 boneless, skinless chicken breasts (about 1 1/2 pounds)
Salt and ground black pepper
2 tablespoons olive oil
1 medium onion, chopped
8 ounces white button mushrooms, brushed clean and sliced (I used more)
4 medium garlic cloves, finely minced or pressed through a garlic press
1 ½ cups long grain white rice
4 cups low-sodium chicken broth
1 large broccoli head, cut up into bite-sized pieces
1/2 cup diced carrots
1 cup shredded sharp or extra-sharp cheddar cheese
½ cup shredded Parmesan cheese
Pat the chicken dry with paper towels and season liberally with salt and pepper. Heat the oil in a 12-inch nonstick skillet over medium heat until the oil is rippling and hot. Carefully lay each chicken breast in the skillet and cook until the chicken is well browned on the first side, about 3-4 minutes. Flip the chicken with a pair of tongs and let it brown on the second side, about 3 minutes. Remove the skillet from the heat and transfer the chicken to a plate and set aside. Drain all but about 1-2 tablespoons oil from the pan.
Return the pan to medium heat. Add the onion, mushrooms, garlic and ½ teaspoon salt and cook, scraping the browned bits off the bottom and edges of the pan, until the mushrooms begin to soften and start to brown, about 6-8 minutes. Add the rice and continue to cook until the edges of the rice turn translucent, about 3 minutes. Add the broth and bring to a simmer. Add the chicken to the pan and cover, reduce the heat to low and cook until the chicken is no longer pink in the center and the rice is mostly cooked through, about 15 minutes.
Remove the chicken from the skillet again, brushing off any rice that sticks to the chicken back into the skillet. Stir the veggies into the skillet well, cover and continue to cook on low until the beans and rice are tender, about 10 minutes. Slice chicken into bite-sized pieces and stir in the chicken and cheese and season to taste with salt and pepper. Serve immediately.