Set your immersion circulator/sous vide to desired finished temperature (I recommend 135 degrees) for 3 hours.
Liberally season your steak with salt, pepper, and garlic powder.
Vacuum seal your steak. If doing more than one, seal them separately.
Place into the water bath, making sure the steak is fully submerged in water.
When time is up, remove the steak. Allow to cool for 10 minutes before opening.
Heat up a grill or a cast iron pan.
When hot, cook the steak for 1-2 minutes per side just to get it hot.
Rest for 5 minutes. Cut slices against the grain and on the bias.