Preheat oven to 350F and grease or line a loaf pan with parchment paper.
Puree your sweet potato by bringing a medium pot of water to a boil. Add sweet potato cubes and bring to a boil once again in the water. Reduce heat and simmer for approximately 20 minutes until the cubes are fork-tender. Transfer to a blender or food processor and puree until creamy and smooth.
In a small bowl, whisk together flaxseed and water and set aside. To a large mixing bowl, add whole wheat flour, baking soda, baking powder, salt, and spices.
In a separate medium mixing bowl, add sweet potato puree, maple syrup, unsweetened applesauce and vanilla extract. Whisk together to combine.
Add wet ingredient mixture to the dry ingredient mixture in the large mixing bowl. Mix together gently until everything is combined, be careful not to over-mix!
Transfer batter to your lined loaf pan and spread evenly. Optional: sprinkle the top with pecan pieces and pepitas. Bake at 350F for 50-60 minutes, until a toothpick comes out clean. Cool sweet potato bread completely, then remove from loaf pan. Slice and serve.