Ingredients

• 6 large heads of garlic, unpeeled, top 1/3 inch cut off to expose garlic
• 6 tablespoons olive oil
• 1/4 cup (1/2 stick) unsalted butter, room temperature
• 2 tablespoons chopped fresh rosemary
• 2 tablespoons Dijon mustard
• 1/2 teaspoon salt
• 1/2 teaspoon ground black pepper
• 1 18- to 19-pound turkey; neck, gizzard and heart reserved
• 1 large onion, chopped
• 2 large celery stalks, chopped
• 1 large carrot, chopped
• 2 1/2 cups dry white wine
• 7 cups (about) canned low-salt chicken broth
• 2 pounds mushrooms, thickly sliced
• 1/3 cup all purpose flour

Instructions

1. Preheat oven to 350°F. Arrange garlic, cut side up, in 8x8x2-inch glass baking dish. Drizzle with 6 tablespoons oil. Cover dish with foil. Bake until garlic is very tender but not yet brown, about 1 hour 20 minutes. Uncover and cool 45 minutes. Squeeze garlic cloves to remove from peel. Place 1 cup garlic cloves in processor (reserve remainder for another use). Add butter, rosemary, mustard, salt, and pepper. Process until almost smooth. Transfer paste to small bowl. (Can be made 4 days ahead. Cover; chill.)
2. For turkey and gravy: Set rack in bottom third of oven and preheat to 350°F. Rinse turkey inside and out; pat dry. Starting at neck end, carefully slide hand between skin and breast meat to loosen skin. Rub 1/2 cup garlic paste over breast meat under skin. If stuffing turkey, spoon stuffing into neck and main cavities. Tuck wings under; tie legs together loosely to hold shape. Place turkey on small rack set in large roasting pan. Rub 2/3 cup garlic paste all over outside of turkey; reserve remaining paste for gravy. Place reserved turkey parts, onion, celery, and carrot in pan around turkey. Boil wine in medium saucepan 2 minutes. Pour 1 cup wine and 1 cup broth into pan. Roast turkey 1 hour. Pour 1 cup broth over turkey; cover turkey breast loosely with foil. Roast 1 hour. Pour 1 cup wine and 1 cup broth over turkey. Cover breast and top of drumsticks loosely with foil. Roast turkey 1 hour. Pour 1/2 cup broth over turkey. Roast uncovered until thermometer inserted into thickest part of thigh registers 175°F, covering any exposed parts of turkey with foil as necessary if over-browning, about 1 hour 10 minutes longer for unstuffed turkey and 1 hour 45 minutes for stuffed. Remove from oven. Using bulb baster, transfer any juices from main cavity of unstuffed turkey to turkey roasting pan. Transfer turkey to platter; let stand 30 minutes (internal temperature of turkey will increase 5 to 10 degrees). Pour turkey pan juices into medium bowl; scrape in any browned bits from pan. Spoon off fat from top of juices, reserving 3 tablespoons fat. Strain juices into large glass measuring cup, pressing hard on solids. Add remaining 1/2 cup wine and enough chicken broth to turkey pan juices to measure 6 cups. Heat reserved 3 tablespoons turkey fat in heavy large pot over medium-high heat. Add mushrooms; sauté until brown and juices evaporate, about 18 minutes. Mix in remaining garlic paste. Sprinkle with flour and stir until flour begins to brown, about 2 minutes. Gradually whisk in 6 cups broth mixture. Bring to boil, scraping up browned bits. Boil until gravy coats spoon lightly, about 8 minutes; season with salt and pepper. Serve turkey with gravy.
3. Set rack in bottom third of oven and preheat to 350°F. Rinse turkey inside and out; pat dry. Starting at neck end, carefully slide hand between skin and breast meat to loosen skin. Rub 1/2 cup garlic paste over breast meat under skin. If stuffing turkey, spoon stuffing into neck and main cavities. Tuck wings under; tie legs together loosely to hold shape. Place turkey on small rack set in large roasting pan. Rub 2/3 cup garlic paste all over outside of turkey; reserve remaining paste for gravy. Place reserved turkey parts, onion, celery, and carrot in pan around turkey. Boil wine in medium saucepan 2 minutes. Pour 1 cup wine and 1 cup broth into pan.
4. Roast turkey 1 hour. Pour 1 cup broth over turkey; cover turkey breast loosely with foil. Roast 1 hour. Pour 1 cup wine and 1 cup broth over turkey. Cover breast and top of drumsticks loosely with foil. Roast turkey 1 hour. Pour 1/2 cup broth over turkey. Roast uncovered until thermometer inserted into thickest part of thigh registers 175°F, covering any exposed parts of turkey with foil as necessary if over-browning, about 1 hour 10 minutes longer for unstuffed turkey and 1 hour 45 minutes for stuffed. Remove from oven. Using bulb baster, transfer any juices from main cavity of unstuffed turkey to turkey roasting pan. Transfer turkey to platter; let stand 30 minutes (internal temperature of turkey will increase 5 to 10 degrees).
5. Pour turkey pan juices into medium bowl; scrape in any browned bits from pan. Spoon off fat from top of juices, reserving 3 tablespoons fat. Strain juices into large glass measuring cup, pressing hard on solids. Add remaining 1/2 cup wine and enough chicken broth to turkey pan juices to measure 6 cups.
6. Heat reserved 3 tablespoons turkey fat in heavy large pot over medium-high heat. Add mushrooms; sauté until brown and juices evaporate, about 18 minutes. Mix in remaining garlic paste. Sprinkle with flour and stir until flour begins to brown, about 2 minutes. Gradually whisk in 6 cups broth mixture. Bring to boil, scraping up browned bits. Boil until gravy coats spoon lightly, about 8 minutes; season with salt and pepper. Serve turkey with gravy.