Heat 1 tbsp oil in a large oven proof pan. Cook the chicken in the pan for 3-4 minutes or until cooked through. Set chicken aside on a plate with paper towel.
Heat another 1 tbsp of oil in a large pan and add leek. Cook for 2-3 minute or until softened slightly.
Add mushrooms and cook for another 3-4 minutes.
Add the rice to the pan and stir in for 1 minute.
Pour in the stock and add cauliflower and chicken to the pan. Stir the contents of the pan together, cover and bring to the boil.
Transfer the pan into the oven and bake for 20 minutes or until the liquid has been absorbed. (Optional: cover with foil to lock in some moisture)
Remove from the oven and stir through parmesan cheese. Serve with chopped parsley.