Fill a large pot with water, add a pinch of salt, and bring to a boil. Add the tortellini and cook according to package directions until al dente, about 3-5 minutes for fresh or longer for frozen. Drain and spread on a baking sheet to cool.
In a small bowl, combine basil pesto, Greek yogurt, lemon juice, salt, and pepper. Whisk until smooth and creamy, adjusting seasoning as needed.
In a large bowl, combine the cooled tortellini, cherry tomatoes, spinach, mozzarella, and Parmesan.
Pour the dressing over the tortellini mixture and toss gently until everything is coated.
Taste the salad and adjust seasoning with salt, pepper, or lemon juice if needed.
Chill in the refrigerator for at least 15 minutes before serving to meld flavors.
Notes
For an inviting presentation, serve in a colorful salad bowl and garnish with fresh basil and pine nuts.