In a medium sized bowl add all wet ingredients and mix until well combined. In a separate bowl mix all dry ingredients, except for cinnamon and 1 1/2 Tbsp of the sugar substitute. Pour wet into dry and combine until batter forms. Coat a donut tray with non-stick baking spray. Add equal amount of batter into each donut mould. Bake at 325F for 8-10 minutes. While donuts are baking put together cinnamon coating. In a plastic bag add the cinnamon and 1 1/2 Tbsp sugar substitute. Shake until well combined. When donuts are done baking, spray them lightly with the cooking spray and coat them with the cinnamon sugar mixture. Serve warm.