Cook the ravioli according to the package directions.
Meanwhile, heat the oil in a medium skillet over medium heat. Add the walnuts and cook, stirring often, until lightly toasted and fragrant, 4 to 5 minutes.
Add the apple, parsley, ½ teaspoon salt, and ¼ teaspoon pepper and toss to combine. Spoon over the ravioli and sprinkle with the Parmesan.