Preheat the oven to 350ºF. Spray three 6-inch cake pans with cooking spray or coconut oil and set aside.
Add 2 ½ cups rolled oats, cinnamon, baking soda, salt, orange juice, applesauce, maple syrup, eggs, oil and vanilla extract to a high powdered blender. Blend until smooth, using a tamper as needed.
Once batter is combined gently fold in remaining 1 ½ cup oats, shredded carrots and raisins.
Pour batter evenly into prepared cake pans and bake for 20-25 minutes until golden brown on top and an inserted toothpick comes out clean.
Allow the cake to cool for about 10 minutes. Remove cake from pans and place on a wire rack to cool completely.
Once cake is at room temperature frost it with the healthy cream cheese frosting and top with chopped walnuts, if desired.
Cut cake and serve.
