In a large pan, combine warm water with kosher salt. Whisk until salt is dissolved.

Squeeze the juice into the water and add the lemon rinds.

Slice garlic cloves in half and place into the brine with rosemary sprigs.

Add ice and stir to cool down the brine.

Lower turkey into brine.

Cover and refrigerate 1- 4 hours.

Drain turkey and discard the brine.

Prepare a grill fire to about 350°. Hickory or pecan chunks will add amazing smoke flavor.

Pat turkey dry with paper towels, inside and out.

Place on a rimmed baking sheet.

Melt to tablespoons of butter in a small pan. Add minced garlic and rosemary, cook 1 minute.

In a small bowl, add softened butter with garlic butter mixture. Use a fork to combine.

Carefully separate the skin from the turkey breast.

Rub butter all under skin and over the top of the the turkey skin.

Sprinkle with dry rub.

Use butcher twine to truss the turkey.

Cook turkey over indirect fire with the grill closed.

Check the turkey about every 30 minutes, turning if it is browning more on one side than the other.

Cook until turkey reaches 160° using a digital meat thermometer the check in the thick part of the thigh, near the bone. 

Remove from grill and rest about 15 minutes before slicing and serving.