Preheat your oven to 400°F (200°C). Roll out the chilled pastry dough on a lightly floured surface until it’s about 1/8 inch thick, aiming for an even layer but embracing the rustic edges. Transfer the rolled dough onto a parchment-lined baking sheet.
Prick the crust all over with a fork to prevent puffing and then bake in the oven for about 15 minutes, or until the edges are golden and crisp. Remove from oven and let cool slightly.
While the crust cools, slice the heirloom tomatoes into thick rounds, about half an inch each. Arrange the slices on a paper towel to absorb excess moisture, then layer them onto the cooled crust, slightly overlapping for a colorful, generous topping.
Sprinkle the crumbled cheese evenly over the tomatoes, adding a tangy, creamy contrast. Scatter chopped basil over the top for fresh aroma and flavor.
Drizzle the tart with a good-quality olive oil and, if using, a splash of balsamic vinegar. Season generously with salt and freshly ground black pepper to enhance all the flavors.
Place the assembled tart back into the oven for an additional 5-10 minutes, just to warm the toppings and meld the flavors. The cheese should soften slightly, and the tomatoes will release some juices, soaking into the crust.
Remove the tart from the oven and let it cool for a few minutes. Slice into wedges, serve slightly warm or at room temperature, and enjoy the vibrant, juicy burst of flavors with every bite.
