2) Meanwhile, in a medium saucepan cook the butter over a medium heat, stirring occasionally. When the foam subsides and the butter begins to turn a golden brown (about 3 minutes) turn off the heat. Allow to cool for about 1 minute. Stir in the balsamic vinegar, salt and pepper.
3) Transfer the ravioli to the pan with the balsamic brown butter. Sprinkle with the walnuts and Parmesan and toss to combine. Transfer to a serving platter and serve immediately.