Instructions

1. Marinate the steaks: Two hours before cooking, whisk all the teriyaki ingredients together. Put the steaks in a gallon zip-top bag, pour in 1/2 cup of the teriyaki sauce, and seal the bag, squeezing out as much air as possible. (Save the rest of the teriyaki sauce for the glazing step.) Flip the bag a few times to coat the steak, then refrigerate, flipping often, until it is time to grill.
2. Set the grill for indirect high heat: Set the grill up for indirect high heat; half the grill with direct high heat, and the other half with no heat. On my Weber kettle I light a full chimney starter of charcoal, wait for it to be mostly covered with gray ash, then pour it in a tight pile over half the grill, two to three coals deep. Then I put the grate on the grill and brush it clean.
3. Slowly cook the steaks over indirect heat: Insert the probe thermometer through the side of the thickest steak, aiming for center mass. Start the steaks on the indirect heat side of the grill, away from the fire. Close the lid and cook the steaks until they reach an internal temperature of 115°F for medium-rare, about 20 minutes. (For Rare, cook to 105°F internal, about 17 minutes; for Medium, cook to 125°F, about 24 minutes.)
4. Sear and glaze the steaks, flipping often: Brush the steaks on both sides with teriyaki sauce, then move the steaks to the direct heat side of the grill. Sear the steaks, brushing with sauce and flipping every minute, until they are browned and crusty on both sides, about 4 minutes. (If you are cooking on a gas grill, rotate the steaks 90 degrees after the second flip to get a diamond crosshatch pattern on the steaks. This doesn’t matter as much with a charcoal grill – charcoal will brown the steaks regardless of the grate direction.) Keep an eye on the steaks as you’re flipping them. Teriyaki sauce burns easily – the steaks will go from browned to blackened if you don’t pay attention.