Pat flank steak dry using paper towels. Add salt and pepper to both sides patting it in. Set aside while you prepare the marinade.
Add all of the liquid ingredients into a medium bowl and stir together to combine.
Using a garlic press (or mincing the cloves on a cutting board) add the garlic to the marinade.
Add the lemon juice and finely chopped green onions. Stir to combine.
Place the flank steak into the zipper bag, then add the marinade making sure there is good contact with all the surfaces. Press all the air out before sealing, and lay on one side in the refrigerator. For best results, let marinate for 4-6 hours, flipping it over a couple of times.
Remove flank steak from the refrigerator 30-60 minutes prior to filling to allow it to come to room temperature.
Pre-heat the grill to medium-high and cook each side for approximately 10-12 minutes or until a meat thermometer reads 130°F. Let rest for at least 5 minutes before slicing against the grain.
Notes
1. A vacuum sealer can cut the marinade time down to an hour. Follow the directions of your equipment for best results, and then let marinate in the refrigerator.2. Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed. The nutritional value is only for the flank steak and does not include anything served with the flank steak such as a salad or tacos. It does not include the nutrition for any substitutions. 3. Be sure to check out the Key Ingredients along with the Recipe Tips and Notes sections found in the post, for more tips, options, substitutions, and variations for this recipe! You will also find step-by-step photos there.