Combine first 3 ingredients in a bowl. Remove giblets and neck from turkey; reserve for other uses. Rinse turkey thoroughly with cold water. Drain body cavity well; pat dry. Rub 1 cup salt mixture over turkey and inside body and neck cavities.
Pour 1 gallon of water into a clean 28-quart cooler. Stir remaining salt mixture into water until dissolved. Place turkey, breast side down, in water. Add crushed ice. Pour remaining water over ice. Close cooler and soak turkey 12 hours.
Remove turkey from brine, discarding brine and unmelted ice. Rinse turkey for several minutes or until all traces of salt are gone; drain and pat dry with paper towels. Place turkey, breast side down, on a cutting board. Using heavy-duty kitchen shears, remove backbone, cutting down each side of bone. Open back of turkey; cut through breast bone with a sharp knife, splitting breast bone completely in half, but leaving breast skin and flesh intact. Turn turkey, breast side up, and press down firmly with heels of hands to flatten.
Place turkey, breast side up, on a rack in a large roasting pan. Tuck wings under, and press down on turkey breast to flatten as much as possible. Turn legs inward, placing knees against breasts. Brush or rub turkey with olive oil.
Roast, uncovered, at 450° for 1 hour and 40 minutes or until a meat thermometer inserted in thigh reaches 180°. Remove turkey to a carving board, reserving drippings in roasting pan. Cover turkey with aluminum foil; let rest 15 minutes.
Meanwhile, prepare sauce. Place roasting pan over 2 burners of stovetop. Whisk flour into drippings until smooth. Gradually whisk wine into drippings. Bring to a simmer over medium heat; cook, whisking constantly, 5 minutes or until sauce thickens. Stir in sage, pepper, and whipping cream; simmer 2 minutes or to desired consistency.
Carve legs and thighs from turkey, and place on a serving platter. Carve each turkey breast half from turkey in 1 whole piece. Cut breast halves crosswise into slices. Arrange breast slices on serving platter. Garnish, if desired. Serve turkey with sauce.
Note: Using a cooler to brine your bird frees up the refrigerator for all the other holiday foods.
Brining a Turkey:
Brining means to soak in a strong salt water solution. The benefits of brining are manyfold.
* The salty soak provides a tenderness cushion for the breast meat, so even if it overcooks by 10 degrees or so, it remains moist.
* The meat of a brined bird tastes pleasantly seasoned, which eliminates the need to season before and after roasting.
* Because the turkey sits overnight in a tub of salted water, brining also ensures that all parts of the turkey are at the same temperature. This is good insurance if you're roasting a previously frozen bird.
* The turkey meat absorbs water during the brining process. Water is a heat conductor and therefore expedites cooking. We tested this theory and found that indeed, a brined bird cooks faster than an unbrined one by about 30 minutes.