01 - Bring a large pot of salted water to a boil. Cook penne pasta according to package directions until al dente. Reserve 1/2 cup pasta water, drain, and set pasta aside.
02 - In a large serving bowl, mix together halved cherry tomatoes, minced garlic, and torn basil leaves.
03 - Transfer warm penne pasta to the bowl. Drizzle with extra virgin olive oil and gently toss to coat. Add reserved pasta water if needed to loosen the mixture.
04 - Fold in fresh mozzarella pieces so they begin to soften from the heat of the pasta.
05 - Season with salt and freshly ground black pepper to taste. Mix in chopped flat-leaf parsley, if using.
06 - Divide among serving plates. Drizzle with balsamic glaze and garnish with extra basil leaves if desired.
07 - Serve immediately, either warm or at room temperature.