Bring a large pot of lightly salted water to a boil. Add tortellini and cook according to package instructions, 3-5 minutes, until they float. Drain and rinse under cold water.

In a small mixing bowl, combine olive oil, balsamic vinegar, Dijon mustard, Italian seasoning, garlic powder, salt, and pepper. Whisk until well blended.

In a large bowl, combine cooked tortellini, cherry tomatoes, olives, bell pepper, cucumber, onion, mozzarella, and Parmesan. Gently toss to mix.

Drizzle the dressing over the salad and toss for 1-2 minutes until evenly coated.

Sprinkle with basil, cover, and chill in the refrigerator for at least 30 minutes before serving.