Pre-heat oven to 350 degrees.
Combine all dry cake ingredients in a large bowl, then mix in all wet ingredients.
Spray two 9 inch round cake pans with non-stick cooking spray. Divide cake mix evenly between 2 cake pans and smooth with a spatula.
Bake at 350 degrees for 25-30 minutes or until a toothpick inserted into the center of the cake comes out clean. Remove from pans and allow to cool on a cooling rack.
Mix Greek yogurt and remaining protein powder until smooth, then add cream cheese and mix until smooth.
Once cakes are cooled, frost the cake. Add a toothpick in the center of the cakes after adding the second layer of cake on top of the first icing layer. Garnish with pecans and cinnamon if desired.
Store in the refrigerator covered.