Preheat the oven to 350º.
Lightly oil an 8″ square baking pan or lay parchment paper across the center and up and out of the pan. This makes it so two ends of the parchment paper are over the opposite sides of the pan. It will be easier for lifting the cake out of the pan.
Mix the egg substitute and set aside. Follow package directions or use any of your favorite substitute. Set aside.
In a medium bowl, combine the sugar and margarine. Use an electric mixer and beat until light and fluffy. This takes about 5 minutes.
Add the egg substitute mix, non-dairy sour cream and vanilla. Mix well.
In a large bowl combine the flour, baking powder and salt. Mix well.
Add the wet ingredients to the dry ingredients and mix until just combined to keep the cake light.
Spoon half of the cake batter into the pan and push it out to the sides.
Sprinkle half of the pumpkin spiced cinnamon sugar mixture over the bottom layer.
Dot the remaining batter in little dabs across the top because it won’t be easy to spread around over the middle layer. So little dabs makes it easier to cover completely.
Sprinkle the remaining pumpkin spiced cinnamon sugar mixture all over the top.
Bake for 40 to 45 minutes or until a toothpick inserted in the center comes out clean.
Let cool in the pan on a wire rack at least 5 to 10 minutes.