Preheat your oven to 375 degrees F. While the sauce is cooking, open the can of biscuit dough and cut the rounds in half with a pair of kitchen shears. Roll the halves into a ball and then press flat with your fingers, making a flat round. Cut small chunks of the brie and place on the rounds, adding some walnuts if using. When the cranberry sauce is cool, add to the rounds. Wrap the dough around the filling, pinching the seams to make sure as little leakage occurs as possible.