In a smaller bowl mix together the apple sauce, apple, maple syrup, egg, and vanilla extract. Mix in the diced apples. Stir the wet into the dry until just mixed.
Pour into the baking dish, and bake for 25-28 minutes, or until a toothpick comes out clean after being inserted into the center. Allow to cool fully before cutting.
After the bars are cooled to room temperature, cut them into 9 pieces.
Wrap the bars in parchment paper, then place them in a sealed bag or airtight container.