Preheat the oven to 500ºF.
Roll out the pizza dough on a lightly floured surface until it is roughly 12 inches wide and 1/4-inch thick.
Invert a baking sheet and sprinkle it liberally with cornmeal. Transfer the dough to the baking sheet.
Brush the pizza dough all over with a 1/2 tablespoon olive oil then bake it until it's golden brown and the crust is crisp around the edges, 10 to 12 minutes.
While the dough is baking, mince 1 clove of garlic and add it to a medium bowl along with the diced tomatoes, chopped basil, 1 tablespoon olive oil, and salt and pepper, to taste. Set the mixture aside.
Boil the balsamic vinegar and sugar in small saucepan until it has reduced to 1/4 cup, about 5 minutes. Set the syrup aside to cool. (See Notes.)
Remove the pizza dough from the oven. Slice the tip off of the remaining garlic clove and immediately rub the cutoff end all over the hot pizza dough.
Slice the pizza into 6 to 8 slices then spoon the tomato mixture on top. Drizzle the tomato mixture with balsamic syrup, garnish with Parmesan cheese and serve immediately.
The balsamic syrup will thicken as it cools. Once it has cooled completely, it can be poured into a bottle and kept in the fridge for up to 2 weeks.
If you cook the balsamic vinegar too long, it'll turn into caramel and then eventually taffy. So when in doubt, undercook it, as it'll thicken significantly as it cools.