Heat a pan.Add butter and few drops of oil. once hot add chopped Onion.
When Onion is soft and looks transparent add minced garlic. fry for 30 seconds.
Add cubed chicken. Cook for 2 minutes on medium-high heat.
Add tomato puree, herbs, chili flakes. mix everything well.
Add Orzo and warm chicken stock. Season with salt.
Once it starts to boil, lower the flame and let it cook slowly.
When almost all the water has been evaporated but still it looks little sauce, switch-off the flame.
At this point, if you want you can add shredded parmesan and give everything a good mix. Else while serving sprinkle some cheese on top.