Remove the tomahawk steak from the fridge at least an hour before cooking. Season the steak liberally with 2 ½ teaspoons salt.
Set the smoker or grill to 250 F. Add the steak to the grill and cook for 90 minutes until it reaches 120 degrees F.
While the steak cooks, make the blueberry compound butter. In a medium mixing bowl, smash together the butter, thyme and blueberries. Chill while you finish the steak.
When the steak reaches temp, remove the steak from the grill. Increase the grill to high/500 F and sear the steak for 2 minutes on each side. Transfer steak onto a cutting board and rest 30 minutes.