Remove your chicken, turkey or beef from the roasting pan and set aside to rest. If there is a lot of fat and drippings leftover, discard all but a few tablespoons. Add 2 tablespoons of flour and 2 tablespoons of butter and start scraping up the browned bits over low heat.
Meanwhile, heat up 2 cups of stock. Once flour and butter from the pan have been amalgamated, add slowly the stock, stirring after each addition until a smooth sauce is formed. Turning up the heat a bit, continue to scrap the bottom of the pan while the gravy thickens. Season with salt and pepper to taste.