1. Preheat oven to 400°F. Remove giblets from cavity and dry turkey inside and out. Using your fingers, gently separate the skin from the breast on each side of the backbone. Smear 2 tablespoon butter on each side of breast beneath the loosened skin.
2. Roughly chop the onion, garlic and apple. Quarter one lemon; set the other one aside for later. Stuff onion, apple, garlic, quartered lemon and herbs into main cavity of turkey. Using kitchen twine, tie the legs together. Spread remaining softened butter over turkey breast, legs and thighs. Sprinkle salt (in moderation) and pepper over turkey. Put flour inside a turkey roasting bag and add giblets. Place turkey inside bag and tie, according to bag directions. Place in a sturdy roasting pan.
3. Place the roasting pan in the oven and roast turkey 30 minutes. Reduce heat to 350°F and roast until an instant read thermometer inserted in turkey thigh reaches 165°F, about 2 hours. Carefully remove turkey from bag (don’t spill juices) and place on a large cutting board. Tent with foil and allow to rest while you make the gravy.
4. To make the gravy, pour the juices from the roasting bag into a medium-sized saucepan (discard the giblets). Add the apple juice and bring to a boil, reducing the sauce until you have a creamy gravy, about 15 minutes. Juice the remaining lemon and add to taste to the gravy (start with half the juice and add more if it needs it) along with salt (in moderation) and pepper if needed.
5. Transfer turkey to a platter and pass the gravy separately.
Per serving: 797 calories, 33g fat, 11g saturated fat, 363mg cholesterol, 594mg sodium, 16g carbohydrate, 2g fiber, 10g sugar, 105g protein