Preheat the oven to 400ºF. To make the balsamic glaze, add the balsamic vinegar and brown sugar to a small saucepot. Place over medium heat and stir to dissolve the sugar. Allow the vinegar to come up to a simmer. Reduce the heat to medium-low and continue to simmer for about 10 minutes, stirring occasionally, or until thickened. Remove from the heat and set aside.
Place the mini naan on a parchment-lined baking sheet. Pre-bake the naan for 5 minutes in the preheated oven.
Slice each Roma tomato into eight slices. Place 1/4 of the shredded mozzarella and four slices of tomato on each piece of naan.
Bake the topped pizzas in the oven for about 7 minutes, or until the cheese is melted and bubby.
While the pizzas are in the oven, thinly slice the basil. Top each pizza with a pinch of salt and pepper, a little fresh basil, and a drizzle of the balsamic glaze just before serving.