Mix all ingredients except for steak and place into a gallon size Ziploc bag. Trim any fat from the flank steak and fold back into thirds. Cut 1/4” thick slices with the grain and place strips of meat into bag with soy sauce mixture and place in a bowl and leave in the refrigerator over night but not more than 24 hours.
When ready to smoke, start smoker and set to 160–170. Lay out jerky with 1/2” between each piece and smoke for 4.5-5 hours. Remove from smoker and enjoy warm or let cool.
If you’re not going to eat your jerky within one or two days store in an airtight container. You can also freeze and keep your jerky for up to six months.