Melt butter in a large saucepan over medium heat.
Add carrots and celery and cook for about 5 minutes.
Add onion and garlic and simmer for 8 minutes.
Add flour and stir to make a roux. Cook until roux begins to brown (this will take a while, so be patient).
Once roux has browned, take pan off stove and let roux come to room temperature.
Pour half and half into small saucepan and warm it slowly.
Once roux has cooled, mix corn and chicken stock in another large saucepan and heat until boiling, then turn temperature down and simmer for 8 minutes.
Carefully and slowly pour corn and stock mixture into the pan with the roux. Mix continuously. It will become very thick.
Add half and half to the thickened mixture and stir. Add diced chicken, nutmeg, red pepper, Riley’s seasoning and salt and pepper to taste.
Cook long enough for the flavors to meld. Be careful not to overcook the soup or the chicken and corn will become rubbery.