Prep your sous vide water bath for 120 degrees F.

Remove the hanger steak from the package and pat it dry with paper towels.

Season all sides liberally with salt.

Using a vacuum seal bag and vacuum sealer, seal the hanger steak in the bag by removing all of the air.

When the water is preheated, submerge the steak in the water, making sure there are no leaks or air pockets.

Allow the steak to cook, submerged in the water for 2 to 3 hours. The steak will reach an internal temp of 120 degrees F with a digital meat thermometer.

Remove the steak from the water bath and plastic bag, reserving any juices for the peppercorn sauce.

Pat the steak dry with paper towels again and cut the steak down the center where the thick silverskin connects the two halves to create two skinny steaks.

Meanwhile, cook the duck-fat fries or traditional thin-cut french fries as directed.

Preheat a carbon steel or cast iron skillet over medium-high heat until just starting to smoke.

Add the butter and quickly swirl to coat.

Place the steaks, garlic, and thyme in the pan.

Using a spoon, baste the steaks in the butter as they quickly sear on all sides, rotating as needed for an even sear.

Immediately remove from the heat. The steak will reach a rare to medium-rare steak temp as it sears and rests.

Set the steaks aside, and in the same pan, proceed with the peppercorn sauce, if desired.