Prepare rice according to package.
Melt the butter in a large pot.
Add in the onion and garlic and saute until onions are translucent.
Add in the arrowroot (or flour), whisking constantly to create a roux over medium heat for another few minutes.
Next, add in mushrooms, carrots, celery, and a little salt and pepper. Saute for maybe 5 minutes, until just softened.
Next add in the broth and bring to a boil.
Reduce to low and then add in the cooked rice and chopped chicken.
Transfer to a crock pot and leave on low for about 2 hours. Add more salt and pepper if needed. Garlic and onion powder also go well. Just add slowly, and taste before adding more!
Add the milk/cream about an hour before serving!
Note: the rice will absorb the liquid, so feel free to add more broth or milk at the end to thin out.
Serve with crusty bread and enjoy!