Cook the tortellini by boiling a large pot of salted water; add tortellini and cook according to package instructions, around 3-5 minutes until they float. Drain and rinse with cold water.

Prepare the veggies by chopping the cherry tomatoes, cucumber, and red onion into bite-sized pieces. Combine in a large bowl with black olives.

Combine the cooled tortellini with the veggies in the bowl. Crumble feta cheese over the mixture and gently mix everything together.

Make the dressing by whisking together olive oil, balsamic vinegar, Dijon mustard, salt, and pepper in a small bowl until emulsified.

Toss the dressing with the tortellini and veggie mixture until well coated. Be careful not to break the tortellini.

Garnish with fresh basil before serving. Enjoy immediately or refrigerate for up to 2 hours before serving.