Blend all the ingredients for the dry rub in a mortar and pestle or spice grinder. Pat the steaks dry and apply dry rub evenly to both sides.

Place each steak in a new Ziploc bag. Close the zip top most of the way, then carefully submerge the bag to force the air out, being careful not to get any water in the bag. Close tightly and repeat with all bags.

Fill the unit with hot tap water and turn on, setting to 140F. This is for Medium steaks. I set it for 2 hours and 10 minutes. Once the unit comes to temperature it will beep three times. Use tongs to place the steak bags into the rack and adjust water level to the Max line before closing the lid. Cook until the timer goes off.

If you wish, reserve the juice from each bag into a small saucepan. Make a slurry from 1 tablespoon of arrowroot powder and 2 tablespoons of the juice, then stir in. Cook over medium heat until the sauce thickens to your liking.

Heat 1 tablespoon of olive oil in a nonstick skillet over high heat until shimmering. Pat steaks dry, then sear for 45 seconds on each side to brown. Serve with chimichurri sauce.

Place garlic and herbs in the food processor and pulse until roughly chopped. Add the rest of the ingredients until finely minced but not puréed. Serve over steak. Use leftover sauce within a week.