Bring 3 to 4 quarts of salted water to a rolling boil in a large pot.
Add the ravioli to the boiling water and cook according to package directions, about 4–6 minutes, until tender and cooked through.
Use a slotted spoon to remove the ravioli from the water and transfer them to a serving bowl, reserving a little pasta water if desired.
Heat the pesto and olive oil together in a small saucepan over low heat or in a microwave-safe bowl for 20–30 seconds until warm and combined.
Spoon the warmed pesto and oil over the cooked ravioli and gently toss to coat, adding a splash of reserved pasta water if needed to loosen the sauce.
Sprinkle the shredded Parmesan cheese over the ravioli and serve immediately.
