Add vinegar to small saucepan bring to a boil.

Reduce heat to low and simmer until reduced by half.

Remove from heat and allow to cool.

Preheat oven to 400.

Add minced garlic to butter and mix well.

Cut the loaf of bread in half lengthwise.

Butter the cut sides with the garlic butter.

Place on a baking sheet with the cut side up.

Place the mozzarella cheese slices on top of the bread.

Bake for about 12 minutes, until cheese is melted and edges are starting to brown.

Top with the sliced tomatoes.

Top tomatoes with chopped basil and salt and pepper to taste.

Drizzle with balsamic reduction.

Cut into slices and serve.