1. In a medium bowl, combine oats, granola cereal, baking powder, wheat germ, cinnamon and salt. Set aside.
2. In another bowl, whisk syrup, milk, egg, vanilla extract, orange juice and zest and sweet potatoes. Pour wet ingredients into dry ingredients and mix well.
3. Spray an 8 x 8-inch baking dish with cooking spray and slide in sweet potato mixture. Bake in a preheated oven at 375 degrees for 15 minutes. Toss walnuts on top and bake another 5-8 minutes. Allow to cool at least 10-15 minutes before cutting.