What’s the trick to applying a glossy, tangy-sweet glaze to turkey so it doesn’t pool at the bottom of the pan or keep the skin from crisping up? America's Test Kitchen finds that butterflying your turkey to create a flatter surface helps to set the scene for a glorious glazed bird.
Note: Table salt is not recommended for this recipe because it’s too fine. If you have a V-rack that, when inverted, still fits into your roasting pan, place the turkey on that rather than on the onions.
1. For the turkey: butterfly turkey. Using fingers or handle of wooden spoon, carefully separate skin from thighs and breast. Using skewer, poke 15 to 20 holes in fat deposits on breast halves and thighs. Rub bone side of turkey evenly with 2 teaspoons salt and 1 teaspoon pepper. Flip turkey skin side up and rub 1 tablespoon salt evenly under skin. Tuck wings under turkey. Push legs up to rest on lower portion of breast and tie legs together with kitchen twine. Combine remaining tablespoon salt, remaining teaspoon pepper, and baking powder in small bowl. Pat skin side of turkey dry with paper towels. Sprinkle surface of turkey with baking powder mixture and rub in mixture with hands, coating skin evenly. Transfer turkey to large roasting pan, skin side up. Place 1 onion half under each breast and thigh to elevate turkey off bottom of roasting pan. Allow turkey to stand at room temperature 1 hour.
2. Adjust oven rack to lower-middle position and heat oven to 275 degrees. Roast turkey until instant-read thermometer registers 160 degrees when inserted in thickest part of breast and 170 to 175 degrees in thickest part of thigh, 2 1/2 to 3 hours. Remove roasting pan from oven and allow turkey to rest in pan for at least 30 minutes or up to 1 1/2 hours. Thirty minutes before returning turkey to oven, increase oven temperature to 450 degrees.
3. For the glaze: While turkey rests, bring cider, cranberries, molasses, vinegar, mustard, and ginger to boil in medium saucepan over medium-high heat. Cook, stirring occasionally, until reduced to 1 1/2 cups, about 30 minutes. Strain mixture through fine-mesh strainer into 2-cup liquid measuring cup, pressing on solids to extract as much liquid as possible. Discard solids (you should have about 1 1/4 cups glaze). Transfer 1/2 cup glaze to small saucepan and set aside.
4. Brush turkey with one-third of glaze in measuring cup, transfer to oven, and roast 7 minutes. Brush on half of remaining glaze in measuring cup and roast additional 7 minutes. Brush on remaining glaze in measuring cup and roast until skin is evenly browned and crispy, 7 to 10 minutes. Transfer turkey to cutting board and let rest 20 minutes.
5. While turkey rests, remove onions from roasting pan and discard. Strain liquid from pan through fine-mesh strainer into fat separator (you should have about 2 cups liquid). Allow liquid to settle 5 minutes, then pour into saucepan with reserved glaze, discarding any remaining fat. Bring mixture to boil over medium-high heat and cook until slightly syrupy, about 10 minutes. Remove pan from heat and whisk in butter. Carve turkey and serve, passing sauce separately.