I am starting with the assumption that you have just removed your brined turkey from the roasting pan and will proceed by reheating the roasting pan on the stovetop (with juice, fat, and tasty brown bits).
Add ¼ cup of flour and heat for several minutes. Then add about 2 cups of chicken stock. Bring to a simmer and cook for 5 minutes. Finish it off by adding ¼ cup (or more) of heavy cream. Basic - but perfection.
*I brine my turkey (let me know if you would like that recipe). This helps add to the flavor of the gravy since the drippings end up on the bottom of the pan. Sometimes I add a little Cognac.