For medium-rare tomahawk steak, heat the precision cooker to 130 degrees. Sprinkle salt, pepper, and garlic powder on both sides of steak. Add one steak per sous vide bag
Seal the bags. Carefully lower the bags into the water bath until they're completely submerged and cook for 3-4 hours
Remove steaks from the bags and pat them dry thoroughly. Rest for 5 minutes. Preheat a cast-iron skillet with one tablespoon of olive oil. Sear each steak for 2-3 minutes on each side. Rest for 5-10 minutes on a foil-tented plate