In a small bowl, combine quinoa flakes, oats, chia seeds, cinnamon, syrup (if using) and almond milk. Stir until combined. Let sit for 5 minutes while you prepare the mango puree.
Peel and chop mango into 1" cubes. Add to a high-speed blender and blend until smooth.
Grab a glass or mason jar and place a layer of overnight quinoa flakes down, then a layer of mango puree, followed by another layer of overnight quinoa flakes, and repeat until you have used all the ingredients.
Transfer to fridge and let sit overnight.
Remove in the morning and enjoy immediately!