Preheat oven to 350 degrees. Line a loaf pan with parchment or spray well with cookie spray. In a food processor, combine chickpeas and applesauce. Place chickpea mixture in a bowl. Add protein powder and water. Mix with your hands until a thick dough forms. Press dough into the prepared loaf pan. Sprinkle with cinnamon, if desired. Bake for 40 minutes. Remove from oven and let cool on wire rack before slicing and serving. Store in the fridge.