Add the stock and the chopped garlic to a medium saucepan and bring to the boil. Lower the heat, add the chicken breast and simmer with the lid on for 20 minutes.
Heat the oil in a very large pan and gently fry the vegetables for about 10 minutes until they are soft. Set aside.
Once the chicken is cooked, remove it to a chopping board and pour the liquid into the large pan with the vegetables returning it to the heat. Use two forks to shred the chicken (this should be pretty easy) and add it to the pan also.
Season with lots of salt and pepper, add the thyme and the brown rice. Bring to the boil, reduce the heat and leave to simmer with the lid on over a medium heat for 25 minutes.
Stir in the sliced mushrooms and cook for another 5 minutes - serve with crusty bread if desired and enjoy!
British food writer splitting time between the English countryside, London's fantastic restaurant scene and rural Northern France. You can taste all of that, as well as the year I spent living and eating out in Los Angeles in my cooking.