Set a sous vide water bath to 130 degrees. Trim the fat cap down to about a ¼-½ inch thickness. Sprinkle salt and pepper on both sides of the steak. Add to sous vide bag
Submerge the bag in the water. Cook for 2 hours or up to 4 hours, maximum
Remove steak from the bag and transfer it to a clean plate. Preheat a skillet with olive oil over medium-high heat. Pat steak dry. Sear on the fat-cap side first for about 5-6 minutes until fat renders down. Then, flip to the other side and sear for 3-4 minutes. Rest for 5-10 minutes on a foil-tented plate