Peel & chop the onion while heating the oil over low-moderate heat.
Cook the onion for 10 minutes or until nearly translucent. Do not burn or caramelise.
Meanwhile, dice the chicken, mushrooms and garlic.
Add the mushrooms, garlic and chicken, and cook for a further 5 minutes. The chicken should be white but only just cooked.
Add the stock to the pan, bring to the boil, then reduce to a simmer.
Chop the spinach finely and remove any stems.
Chop the herbs and add to the pan.
Add salt and pepper to taste.
Add the rices and cook a further few minutes.
Grate the cheese, add it to the pan and mix through.
Remove the pan from the heat and mix the spinach through.
Serve in ramekins topped with shallots.