Cook the rotini pasta according to the package directions until al dente. Drain the pasta and rinse under cold water to stop the cooking process and cool it down completely.

Transfer the cooled pasta to a large mixing bowl. Add the cherry tomatoes, mozzarella pearls, chopped basil, and red onion if using. Gently toss everything together so the ingredients are evenly distributed throughout the pasta.

In a small bowl or jar, whisk together the olive oil, balsamic glaze, balsamic vinegar, Italian seasoning, minced garlic, salt, and black pepper until fully combined and smooth.

Pour the dressing over the pasta salad and toss thoroughly so all the pasta and ingredients are lightly coated with the flavorful dressing.

Cover the bowl and refrigerate the pasta salad for at least 30 minutes before serving to allow the flavors to blend together.

Before serving, give the salad another gentle toss and drizzle with a little extra balsamic glaze if desired for extra flavor and presentation. Serve chilled or slightly cool.