Bring a large pot of salted water to a boil. Cook tortellini according to package directions until al dente. Drain, rinse briefly with cold water to stop cooking, and let cool completely.

In a small bowl, whisk together pesto, lemon juice, olive oil, salt, and pepper until smooth. Set aside.

In a dry skillet over medium heat, toast pine nuts, stirring frequently, until golden and fragrant, about 2–3 minutes. Immediately transfer to a plate to cool.

In a large bowl, combine cooled tortellini, sun-dried tomatoes, mozzarella pearls, toasted pine nuts, and torn basil. Pour dressing over and toss gently until everything is coated.

Top with shaved Parmesan and extra basil. Serve immediately or refrigerate for up to 3 days. Allow to come to room temperature for best flavor.