Bring a large pot of salted water to a boil over high heat. Add the ravioli and cook 4 to 5 minutes, until tender but still firm to the bite, stirring occasionally. Drain ravioli onto a large serving platter.
Meanwhile, in a medium saucepan cook the butter over medium heat, stirring occasionally. When the foam subsides, and the butter begins to turn a golden brown, about 3 minutes, turn off the heat. Let cool for about 1 minute. Stir in the balsamic vinegar, salt, and pepper.
Transfer the ravioli to the pan saucepan with the balsamic brown butter. Sprinkle walnuts and Parmesan over the top. Serve immediately.
Recipe courtesy of Giada De Laurentiis