Step 1

Fill a deep container 3/4 of the way full with water. And set your immersion circulator in the water. Heat the circulator to 130.5 F.

Step 2

While the water comes to temperature, mix the salt, cumin and coriander together in a small container.

Step 3

Set the flank steak on a cutting board, and pat it dry. Sprinkle the spices and salt evenly over both side of the steak, and then tuck it into a FoodSaver gallon-sized vacuum seal bag. Vacuum and seal the steak.

Step 4

Place the vacuum-sealed steak into the preheated water, and let it cook for 3 hours.

Step 5

About 5 minutes before steak is finished cooking, make the herb sauce. Stir the herbs together with jalapeño pepper, shallot and garlic. Next, stir in the olive oil, lemon juice and sea salt. Set aside.

Step 6

Turn off the immersion circulator, remove the bag from the water, and then open the bag. Heat a cast iron skillet over medium-high heat until hot. Swirl olive oil into the pan, and then gently place the steak into the skillet. Sear about 3 minutes on each side, or until it forms a nice crust. Slice the steak against the grain in thin strips, and serve warm with herb sauce.