In a baking dish large enough to hold the steak, whisk together the olive oil, coconut aminos, lime juice, minced garlic, salt and pepper. Add the flank steak, turn to coat in marinade, and cover with plastic wrap. (Alternatively, you can whisk the marinade in a small bowl, place the steak in a zip lock bag, pour the marinade over it, seal, and move around to coat.)

Refrigerate the flank steak in marinade for at least 2 hours, up to to 24 hours, turning the meat halfway through if possible. (Don’t do longer than 24 hours, or the meat will get mushy.)

If you can, take the flank steak out of the refrigerator and let it sit at room temperature for about 30 minutes before cooking.

Preheat the broiler to 500 degrees F (260 degrees C). Place the oven rack about 6 inches from the heating element.

Place the steak on a sheet pan and place in the oven. Broil the flank steak, flipping halfway through, for 8-12 minutes for rare, 10-14 minutes for medium rare, 14-18 minutes for medium, 16-20 minutes for medium well, or 18-22 minutes for well done. The time will vary depending on your steak thickness and oven, so use a meat thermometer to be sure – 120 degrees F (49 degrees C) for rare, 130 degrees F (54 degrees C) for medium rare, 140 degrees F (60 degrees C) for medium, 150 degrees F (66 degrees C) for medium well, and 160 degrees F (71 degrees C) for well done. Steak temperature will increase by an additional 5 degrees when resting in the next step.

Transfer the steak to a plate or cutting board. (Do not leave it in the pan or it will be overcooked.) Tent with foil and let it rest for 5 minutes before slicing against the grain.

Oil the grill grates well. Preheat the grill to high heat (450-500 degrees F (232-260 degrees C).

Place the flank steak on the grill over direct heat. Grill for 3-4 minutes per side for rare, 4-5 minutes per side for medium rare, 5-6 minutes per side for medium, 6-7 minutes per side for medium well, or 7-8 minutes per side for well done. The time will vary depending on your steak thickness and grill, so use a meat thermometer to be sure – 120 degrees F (49 degrees C) for rare, 130 degrees F (54 degrees C) for medium rare, 140 degrees F (60 degrees C) for medium, 150 degrees F (66 degrees C) for medium well, and 160 degrees F (71 degrees C) for well done. Steak temperature will increase by an additional 5 degrees when resting in the next step.

Transfer the steak to a plate or cutting board. Tent with foil and let it rest for 5 minutes before slicing against the grain.

Preheat a large cast iron skillet to medium-high heat. Make sure it’s very hot before adding the steak.

Add oil to pan just before cooking.

Add the steak and sear for 3-4 minutes per side for rare, 4-5 minutes per side for medium rare, 5-6 minutes per side for medium, 6-7 minutes per side for medium well, or 7-8 minutes per side for well done. (Do not move the steak around except to flip.) The time will vary depending on your steak thickness and grill, so use a meat thermometer to be sure – 120 degrees F (49 degrees C) for rare, 130 degrees F (54 degrees C) for medium rare, 140 degrees F (60 degrees C) for medium, 150 degrees F (66 degrees C) for medium well, and 160 degrees F (71 degrees C) for well done. Steak temperature will increase by an additional 5 degrees when resting in the next step.

Transfer the steak to a plate or cutting board. (Do not leave it in the pan or it will be overcooked.) Tent with foil and let it rest for 5 minutes before slicing against the grain.