Begin by adding all the marinade ingredients to a large zip-top bag or bowl. Mix everything to combine well then add the steak. Seal the bag or cover the bowl and place in the refrigerator to marinate for 3-4 hours.
Once the steak has had enough time to marinate, take it out of the refrigerator and heat a grill pan or outside grill.
While the grill preheats, begin assembling the salad. Slice the heirloom tomatoes into about 1/2" slices and the cherry tomatoes in half. Arrange them on a large platter or individual plates. Sprinkle with a little sea or kosher salt.
Remove the fresh mozzarella from it's water and pat dry just to remove any excess liquid. Then tear off bite-sized pieces and place in between and around the tomatoes. Do the same with the basil leaves, tearing larger leaves into smaller pieces if desired.
When the grill is sizzling hot, remove the steak from the marinade, discard the marinade and grill the steak for about 3 minutes per side for medium/ medium rare or a minute or two longer if desired. It should get nice and charred. Let the steak rest on a cutting board for 10 minutes, then slice it diagonally against the grain.
While the meat is resting, drizzle the slices of sourdough on each side with a little olive oil. Place on the hot gril then grill for just a couple minutes per side to get it toasty with those nice grill marks. Soon as you remove the bread from the grill, lightly rub one side of each slice with the cut end of the garlic. (this will smell divine)
Now top the salad with the sliced steak and arrange the toast around the platter. Drizzle the whole salad or plates with a little more olive oil and a sprinkling of salt and pepper. Right before serving, give a light drizzle of balsamic vinegar. Enjoy!