Season the flank steak with salt and black pepper on both sides.

In a small bowl, whisk together olive oil, balsamic vinegar, honey, and garlic powder. Reserve half of the marinade for serving.

Place the steak in a large resealable plastic bag or shallow dish and pour the remaining marinade over it. Seal the bag or cover the dish and marinate in the refrigerator for at least 1 hour, or up to 8 hours for more flavor.

Preheat the grill to medium-high heat. Remove the steak from the marinade and discard the marinade.

Grill the steak for 5-7 minutes on each side for medium-rare, or until it reaches your desired doneness. Remove from the grill and let it rest for 5 minutes.

While the steak is resting, combine the cherry tomatoes, mozzarella, and basil in a bowl. Drizzle with the reserved marinade and toss gently to combine.

Slice the steak against the grain into thin strips. Serve topped with the Caprese salad mixture.