The first step in making Pioneer Woman's London Broil is to make the marinade. In a large bowl, whisk together the soy sauce, olive oil, balsamic vinegar, Worcestershire sauce, honey, Dijon mustard, and minced garlic. Season the marinade with salt and pepper to taste.

Once the marinade is ready, place the flank steak in a large, shallow dish. Pour the marinade over the steak, making sure that it's fully coated. Cover the dish with plastic wrap and refrigerate for at least 2 hours, or overnight if possible. This will allow the flavors to fully penetrate the meat.

When you're ready to cook the London Broil, preheat your grill or broiler to high heat. If you're using a grill, make sure that it's clean and oiled to prevent the steak from sticking.

Remove the steak from the marinade and discard the remaining marinade. Place the steak on the grill or under the broiler and cook for 4-5 minutes per side, or until the internal temperature reaches 135°F for medium-rare or 145°F for medium. Use a meat thermometer to ensure that the steak is cooked to your desired level of doneness.

Once the steak is cooked to your liking, remove it from the grill or broiler and let it rest for 5-10 minutes before slicing. This will allow the juices to redistribute and make the steak more tender. After the steak has rested, slice it thinly against the grain and serve with your favorite sides.