1 (12-to 14-pound) turkey, neck and giblets (excluding liver) reserved for turkey stock
2 1/2 cups water, divided
About 4 cups hot turkey giblet stock
Melted unsalted butter if necessary
5 tablespoons all-purpose flour
3/4 cup heavy cream


Equipment: a 17- by 14-inch flameproof roasting pan with a flat rack; kitchen string; a 2-quart measuring cup or a fat separator

Rinse turkey inside and out and pat dry. Put turkey on rack in roasting pan and season inside and out with 1 tablespoon salt and 2 teaspoons pepper. Fold neck skin under body, then tuck wing tips under breast and tie drumsticks together with string. Let stand at room temperature 1 hour.

Preheat oven to 450°F with rack in lower third.

Add 1 cup water to pan and roast, without basting, rotating pan halfway through, until an instant-read thermometer inserted into fleshy part of each thigh (test both; do not touch bone) registers 165 to 170°F, 1 3/4 to 2 hours total.

Carefully tilt turkey so juices from inside large cavity run into pan. Transfer turkey to a platter (reserve juices in roasting pan) and let rest, uncovered, 30 minutes (temperature of thigh meat will rise to 170 to 175°F). Discard string.

Make gravy while turkey rests:
Strain pan juices through a fine-mesh sieve into 2-quart measure and skim off fat (or use a fat separator), reserving fat. Straddle roasting pan across 2 burners, then add remaining 1 1/2 cups water and deglaze pan by boiling over high heat, stirring and scraping up brown bits, 1 minute. Strain through sieve into measuring cup containing pan juices. Add enough turkey giblet stock to pan juices to bring total to 5 cups.

Put 5 tablespoons reserved fat (if there is less, add melted butter) in a 4-quart heavy saucepan and whisk in flour. Cook roux over medium heat, whisking, 3 minutes. Add stock mixture in a fast stream, whisking constantly, then add cream, 1 teaspoon salt, and 1 1/2 teaspoons pepper. Bring to a boil, whisking, then stir in any turkey juices from platter and simmer 5 minutes. Put 5 tablespoons reserved fat (if there is less, add melted butter) in a 4-quart heavy saucepan and whisk in flour. Cook roux over medium heat, whisking, 3 minutes. Add stock mixture in a fast stream, whisking constantly, then add cream, 1 teaspoon salt, and 1 1/2 teaspoons pepper. Bring to a boil, whisking, then stir in any turkey juices from platter and simmer 5 minutes.

Serve turkey with gravy.