In a zip-top bag or shallow dish, combine olive oil, minced garlic, salt, and black pepper to create the marinade for the steak. Add the flank steak, ensuring it's evenly coated. Seal and refrigerate for 1 to 8 hours.

Preheat your grill to medium-high heat, about 400°F to 450°F, ensuring the grates are clean.

Remove the flank steak from the marinade and grill each side for 4 to 5 minutes, or until it reaches an internal temperature of 130-135°F for medium-rare.

Transfer the steak to a cutting board and let it rest for 5 to 10 minutes.

In a medium-sized bowl, combine halved cherry tomatoes, mozzarella balls, and chopped basil. Drizzle with olive oil and sprinkle with salt.

Slice the rested flank steak thinly against the grain and arrange it on a platter with the Caprese salad. Drizzle with balsamic glaze before serving.