Prepare the Turkey: Make sure your turkey is fully thawed. Remove the giblets and neck from the cavity and set them aside for gravy.
Make the Injection: In a bowl, combine the melted butter, basil-infused olive oil, MSG, granulated garlic, and granulated onion. Mix thoroughly. Use a meat injector to inject this mixture throughout the turkey, focusing on the breasts, legs, and thighs.
Season the Turkey: Rub any remaining injection mixture over the outside of the turkey. In a separate shaker, combine all ingredients for the spice rub, then sprinkle generously over the entire turkey.
Stuff the Turkey: Place the onion quarters and head of garlic inside the cavity of the turkey for added flavor.
Truss the Turkey (Optional): Use a Turbo Trusser or truss the turkey by hand, tucking the wings under to keep everything in place.
Set Up the Grill: Preheat your pellet grill with hickory and oak pellets. Set the grill to its smoke setting and let it reach around 190°F (88°C).
Smoke the Turkey: Place the turkey on a sheet pan with a grill grate underneath to catch drippings. Add the next and other parts to the pan and Smoke the turkey for 1-2 hours to infuse deep smoky flavor. Remove the neck and other parks after 2 hours to use for the gravy.
Adjust the Temperature: Raise the grill temperature to 275°F (135°C) and continue cooking the turkey for 2-3 hours. Spray the turkey with olive oil midway through to help crisp the skin.
Finish at Higher Heat: For the last hour, increase the grill temperature to 350°F (175°C) to crisp the skin. Continue cooking until the internal temperature of the breast reaches 165°F (74°C) and the thighs reach 175°F (79°C).
Rest and Carve: Remove the turkey from the grill and let it rest for 30 minutes before carving.