Preheat the oven to 325 degrees.
Beat the egg substitute, buttermilk, and vanilla together in a bowl and set aside. Combine the dry ingredients, except the walnuts, in another bowl. Add the egg-milk mixture and chopped walnuts.
Pour the mixture into a 10-inch Bundt pan or a large loaf pan sprayed with nonstick spray.
Bake 45 minutes to 1 hour. Turn onto a wire rack and cool before serving.
Makes 12 servings