1Combine the marinade ingredients in a glass bowl and whisk together to combine thoroughly. 2Place the London broil steak in a large, re-sealable bag. 3Pour in the marinade and seal the bag, squeezing out as much air as possible and then place the bag in a refrigerator for 4 - 6 hours or overnight. Turn the bag at least once during that time to make sure all of the sides of the steak get some soy lovin'.