How to Make It
Preheat oven to 300°F.
Cut about 1/2 inch from top of garlic heads; wrap heads in foil. Bake at 300°F for 1 1/2 hours or until very soft. Remove from oven; cool completely. Separate garlic cloves; squeeze to extract garlic pulp. Discard skins. Combine garlic pulp, butter, chopped sage, rind, salt, and red pepper in a bowl.
Increase oven temperature to 425°F.
Remove giblets and neck from turkey; reserve. Pat turkey dry.
Starting at neck cavity, loosen skin from breast and drumsticks by inserting fingers, gently pushing between skin and meat. Rub butter mixture under loosened skin. Lift wing tips up and over back; tuck under turkey. Place sage sprigs, lemon, and onion in body cavity. Secure legs with kitchen twine. Place turkey, breast side up, on the rack of a roasting pan coated with cooking spray. Place neck in bottom of roasting pan; place rack with turkey in pan. Add 1/2 cup water to pan. Bake at 425°F for 40 minutes.
Combine oil, wine, and mustard in a bowl, stirring with a whisk. Baste turkey with half of oil mixture.
Reduce oven temperature to 350°F (do not remove turkey from oven). Bake at 350°F for 1 hour and 15 minutes. Rotate turkey from front to back; baste with remaining half of oil mixture. Bake at 350°F for 10 to 20 minutes or until a thermometer inserted into thickest part of thigh registers 160°F. Remove from oven; place turkey on a cutting board. Let stand, loosely covered with foil, 20 minutes (internal temperature will rise to 165°F). Remove skin before carving. Reserve pan drippings and neck for gravy, if using.