Cook the tortellini: Bring a large pot of salted water to a boil. Add the tortellini and cook according to package instructions until tender. Drain and rinse under cold water to stop cooking and cool completely. Set aside.

Prepare the mix-ins: While the tortellini is cooking, chop sun-dried tomatoes, slice olives, and dice red onion. If using pine nuts, toast them lightly in a dry skillet over medium heat for 2–3 minutes until golden and fragrant, stirring constantly to prevent burning.

Combine the salad: In a large mixing bowl, add the cooled tortellini. Stir in the basil pesto, making sure every piece is evenly coated in the vibrant green sauce.

Add flavor and texture: Gently fold in sun-dried tomatoes, black olives, red onion, and mozzarella. Drizzle with extra virgin olive oil, then season with salt and black pepper to taste. Toss everything together until well mixed, being careful not to break the tortellini.

Garnish and serve: Transfer the salad to a serving bowl or platter. Sprinkle toasted pine nuts on top and garnish with fresh basil leaves for color and aroma. Chill in the refrigerator for 15–20 minutes before serving if you prefer a colder, more refreshing dish. Serve cold as a side dish or light main.