Heat the oil in large skillet over medium heat. Add the hazelnuts and cook, stirring, until golden and fragrant, 5-6 minutes; remove from heat.
In the meantime, cook the ravioli according to package instructions and drain, reserving ½ cup of the pasta cooking water. Add the drained ravioli to the skillet with the hazelnuts, add the basil leaves and toss, adding a little of pasta cooking water to loosen the sauce, if needed. Season with salt and pepper to taste. Divide among plates and top with additonal basil leaves and hazelnuts.