After simmering for some time (or however long you can wait!), combine the remaining 1/2 cup of chicken broth and arrowroot powder to create a slurry. Add the mixture to your soup and stir* for a minute. This will begin to thicken everything up. *Make sure to stir from the bottom. Sometimes, the slurry will fall towards the bottom of the pot and thicken everything much faster down there. Then your soup will have gravy-like chunks in it. No good. …well, gravy-like clumps don’t sound all that bad to me. Remember, though, I like my gravy! Anyways, STIR IT GOOD!