PreparationFor prosciutto butter: Place butter in large bowl. Mix in hazelnuts, vinegar, thyme, crushed pepper, garlic, and salt. Mix in prosciutto and green onions. For gravy base: Melt 2 tablespoons prosciutto butter in heavy large pot over medium-high heat. Add neck, heart, gizzard, shallots, and bay leaf; sauté until brown, about 20 minutes. Add wine, thyme, and rosemary; boil until liquid is reduced almost to glaze, about 3 minutes. Add 4 cups broth; bring to boil. Reduce heat to medium-low, cover, and simmer until giblets and neck are tender, about 1 hour. Discard bay leaf and thyme sprig. Transfer neck and giblets to work surface. Chop enough giblets to measure 1 cup. Remove meat from neck and chop. Combine neck meat and chopped giblets in bowl with broth from pot. (Prosciutto butter and gravy base can be made 1 day ahead. Cover and chill butter; bring to room temperature before using. Chill gravy base until cold, then cover and keep chilled.) For turkey: Set rack at lowest position in oven and preheat to 325°F. Rinse turkey inside and out; pat dry. Starting at neck end, slide hand between skin and breast, thigh, and leg meat to loosen skin. Set aside 1/4 cup prosciutto butter for gravy. Spread 1 cup prosciutto butter over turkey meat under skin. Spread 1 cup prosciutto butter over outside of turkey. Sprinkle turkey inside and out with salt and pepper; place on rack set in large roasting pan. Place onion and next 4 ingredients in main turkey cavity. Tuck wing tips under; tie legs together loosely. Roast turkey uncovered 1 1/2 hours. Tent turkey with foil; add 2 cups broth to pan. Roast until thermometer inserted into thickest part of thigh registers 175°F, occasionally basting with pan drippings and adding more broth to pan, about 2 hours longer. Transfer to platter; tent with foil. Let stand 30 minutes (internal temperature will increase 5 to 10 degrees). Strain pan juices into 8-cup measuring cup; spoon fat off top. Add reserved gravy base. Add enough chicken broth to mixture to measure 5 cups total. Melt reserved 1/4 cup prosciutto butter in heavy large pot over medium-high heat. Add flour; whisk 1 minute. Gradually add pan-juice mixture, whisking constantly. Boil, whisking frequently, until gravy is very slightly thickened, about 5 minutes. Season with salt and pepper. Serve turkey with gravy.
PreparationFor prosciutto butter: Place butter in large bowl. Mix in hazelnuts, vinegar, thyme, crushed pepper, garlic, and salt. Mix in prosciutto and green onions. For gravy base: Melt 2 tablespoons prosciutto butter in heavy large pot over medium-high heat. Add neck, heart, gizzard, shallots, and bay leaf; sauté until brown, about 20 minutes. Add wine, thyme, and rosemary; boil until liquid is reduced almost to glaze, about 3 minutes. Add 4 cups broth; bring to boil. Reduce heat to medium-low, cover, and simmer until giblets and neck are tender, about 1 hour. Discard bay leaf and thyme sprig. Transfer neck and giblets to work surface. Chop enough giblets to measure 1 cup. Remove meat from neck and chop. Combine neck meat and chopped giblets in bowl with broth from pot. (Prosciutto butter and gravy base can be made 1 day ahead. Cover and chill butter; bring to room temperature before using. Chill gravy base until cold, then cover and keep chilled.) For turkey: Set rack at lowest position in oven and preheat to 325°F. Rinse turkey inside and out; pat dry. Starting at neck end, slide hand between skin and breast, thigh, and leg meat to loosen skin. Set aside 1/4 cup prosciutto butter for gravy. Spread 1 cup prosciutto butter over turkey meat under skin. Spread 1 cup prosciutto butter over outside of turkey. Sprinkle turkey inside and out with salt and pepper; place on rack set in large roasting pan. Place onion and next 4 ingredients in main turkey cavity. Tuck wing tips under; tie legs together loosely. Roast turkey uncovered 1 1/2 hours. Tent turkey with foil; add 2 cups broth to pan. Roast until thermometer inserted into thickest part of thigh registers 175°F, occasionally basting with pan drippings and adding more broth to pan, about 2 hours longer. Transfer to platter; tent with foil. Let stand 30 minutes (internal temperature will increase 5 to 10 degrees). Strain pan juices into 8-cup measuring cup; spoon fat off top. Add reserved gravy base. Add enough chicken broth to mixture to measure 5 cups total. Melt reserved 1/4 cup prosciutto butter in heavy large pot over medium-high heat. Add flour; whisk 1 minute. Gradually add pan-juice mixture, whisking constantly. Boil, whisking frequently, until gravy is very slightly thickened, about 5 minutes. Season with salt and pepper. Serve turkey with gravy.