Melt the butter in a large Dutch oven or soup pot. Saute the carrots, celery, and onion for 10 minutes over medium heat, stirring often, until the onions are translucent. Add the garlic after 5 minutes. Note: don't brown the veggies, just gently saute.
Stir in the flour and cook for a minute or two more, again, without browning the flour.
Add the Sherry to the pot, and give everything a good stir, then add the broth, along with the bundle of thyme and bring to a gentle boil, stirring often.
Add the cooked rice, and teaspoon of salt and pepper. Cover and gently simmer for 5 minutes. Note: check the pan often to make sure it is simmering and not furiously boiling.
Remove the thyme bundle, add the evaporated milk and half and half, and heat through. Taste to adjust the seasonings.
At this point the soup can be cooled and refrigerated overnight. Or you can enjoy right away.
Notes
how to cook wild rice
1 cup of raw rice will yield 4 cups cooked rice.
Place the rice in a tall sided saucepan and cover with several inches of cold water.
Bring to a boil, then reduce heat, cover, and let simmer for 40-50 minutes, or until just tender.
Some of the rice will have split open, but it should still have a nice chewy texture. Taste it to check, and don't over cook.