Combine water, kosher salt, brown sugar, peppercorns, garlic, molasses, bay leaves, rosemary, and cinnamon stick in a large pot. Bring to a boil and stir until salt and sugar are dissolved.
Remove brine from heat and allow to cool.
Place clean uncooked turkey into food grade container. Pour cooled brine and ice over the turkey. Seal the container and allow to rest for 16-24 hours at 40°F (or below).
Discard brine solution and rinse turkey with water. Pat dry and allow to air dry before cooking.