Preheat oven to 350F. Spread walnuts on a lined baking sheet. Bake for 7-8 minutes, or until golden and toasty. Set aside.Spray an 8x8 inch baking dish with cooking spray and set aside.Place flax and water in a small bowl, stirring to combine. Set aside to gel for 5 minutes.Place ½ cup oats in a blender or food processor (I used my Nutribullet). Blend until it resembles flour. Dump into a large mixing bowl and stir in remaining 2 cups of oats, coconut sugar, cinnamon, salt, and toasted walnuts.Mash bananas in a separate medium mixing bowl. Add almond milk, applesauce, vanilla, and flax mixture. Mix well then fold in apple, carrot, and cranberries. Pour wet mixture into dry and stir until just combined.Pour into prepared dish. Top with thinly sliced apple if desired and bake for about about 40 minutes.Slice into 9 pieces. Top with pure maple syrup, nut butter, or toppings of choice. Eat room temp as a snack bar or heat in microwave for a quick breakfast!