In a small sauce pan, pour in the half cup of balsamic vinegar. Bring to a small boil and reduce to a simmer until the vinegar has reduced to about 4 tablespoons. Be careful not to let it burn!

To assemble sandwiches; drizzle the inside of the top hoagie half with a little bit of olive oil, and drizzle the bottom half with the reduced vinegar.

Top the bottom half with slices of fresh tomato and sprinkle with kosher salt and black pepper. Top the tomatoes with fresh basil and slices of fresh mozzarella. If there's any mozzarella slices leftover you can save them or snack on them. I opt for the latter ;).

Replace the top bun and place it in your panini press. Panini the sandwich for about 4-5 minutes until the sandwich is completely pressed and cheese is oozing out the sides {holla!}.

Let cool slightly before slicing in half with a sharp knife.