01 - Bring a large pot of salted water to a rolling boil. Cook the pasta until al dente, following package directions. Reserve 1/2 cup of the pasta cooking water, then drain the pasta.
02 - While the pasta is cooking, heat the extra virgin olive oil in a large skillet over medium heat. Add the thinly sliced garlic and finely chopped red onion. Sauté for 2 to 3 minutes until fragrant and translucent.
03 - Introduce the diced heirloom tomatoes, sea salt, freshly ground black pepper, and crushed red pepper flakes (if using) to the skillet. Cook for 7 to 8 minutes, stirring gently, until the tomatoes have softened but still retain some structural integrity.
04 - Add the drained pasta to the skillet with the cooked tomatoes. Toss to ensure an even coating. Incorporate the reserved pasta water, adding it a little at a time, until a silky sauce consistency is achieved.
05 - Remove the skillet from the heat. Stir in the torn fresh basil leaves until just wilted.
06 - Portion the pasta equally among serving plates. Crown each serving with aged balsamic pearls, shaved Parmigiano-Reggiano (if using), and additional fresh basil leaves.
07 - Present the dish immediately.