Perfect Turkey Gravy
Do not use a non stick pan when cooking your turkey. This way, there will be more crispy, cooked-on bits, which add flavor to the gravy.
Make giblet stock while turkey is roasting.
Transfer roasted turkey to a large platter. Pour juices from the pan into a fat separator. Set aside to separate, about 10 minutes.
Strain stock, discarding solids, and return to saucepan; warm over low heat. Place roasting pan on top of stove over medium-high heat. Pour Madeira into measuring cup, then into pan, and let it bubble; scrape bottom and sides of pan with a wooden spoon to dislodge cooked-on bits.
Make a slurry: Place flour in a glass jar with a tight-fitting lid. Ladle 1 cup stock into jar, and close lid. Shake until combined. Slowly pour into roasting pan; stir to incorporate. Cook over medium heat, stirring until flour is cooked, 2 to 3 minutes. Slowly stir in remaining stock.
Raise heat to medium high. Add the dark drippings that have settled to the bottom of the fat separator to roasting pan. Discard fat. Stir in rosemary. Season with salt and pepper. Cook 10 to 15 minutes to reduce and thicken. (For thicker gravy, add 1 more tablespoon flour and 1/2 cup less stock.)
Strain liquid from pan through a very fine sieve. Adjust seasoning. Keep warm in heat-proof bowl over a pan of simmering water until ready to serve.