Prepare your grill for indirect heat cooking. For a gas grill, preheat to low heat (around 325°F/165°C) with burners lit on one side only. For charcoal, arrange coals on one side of the grill and maintain a steady, low temperature.

Thoroughly rinse the turkey inside and out under cold water, then pat dry with paper towels.

In a small bowl, combine the dry spices: garlic powder, paprika, onion powder, thyme, salt, and pepper.

Rub the turkey all over with olive oil, including under the skin where possible. This helps the spices stick and promotes crispy skin.

Season generously with the spice mixture, making sure to get some inside the cavity and under the skin.

Stuff the cavity with the quartered apples and onions. These will infuse moisture and flavor throughout the cooking process.

Place the turkey breast-side up in a disposable aluminum pan or on a drip pan.

Pour the white wine and chicken broth into the pan around (not over) the turkey.

Position the pan on the cooler side of the grill (away from direct flames).

Close the grill lid and maintain a consistent temperature between 300-325°F (150-165°C).

After the first hour, begin basting the turkey with the melted butter every 30 minutes.

Cook until a meat thermometer inserted into the thickest part of the thigh (without touching bone) registers 165°F (74°C). For a 15-pound turkey, this will take approximately 4 to 4.5 hours.

If parts of the turkey are browning too quickly, cover them with small pieces of aluminum foil.

Once done, remove from the grill and tent loosely with foil. Let rest for 20-30 minutes before carving to allow juices to redistribute.

Carve and serve your delicious BBQ turkey to your amazed family and friends!