This is a very simple smoked turkey recipe, however it is flexible and you can make changes to it to suit your tastes. You could add apple on the inside or rub rosemary on the skin. Feel free to experiment with this and develop your favorite flavor.
Preheat smoker to 225 degrees.
Melt your stick of butter.
Rinse turkey under cold water, and pat dry.
Mix the 1/4 tsp garlic powder, the seasoning salt and half of your melted butter. Place turkey in a disposable roasting pan. Use a basting brush to spread mixture over the outside of the turkey.
Fill the turkey cavity with remaining butter, cola, onion, garlic powder, salt, and pepper. Cover loosely with foil.
Smoke at 225 degrees for 8 hours, or until internal temperature reaches 165 degrees when measured in the thickest part of the thigh. Depending on the size of your turkey, you might want to check at 6 or 7 hours to make sure it doesn't overcook. Each smoker is slightly different. Baste the turkey every 2 hours with the juices from the bottom of the roasting pan.
Save the remaining juices at the bottom of the roasting pan and use to make gravy.