In a large bowl, stir together the flour, cinnamon, baking soda, baking powder and kosher salt. In a separate bowl, whisk together the eggs, then the milk, brown sugar, sweet potato puree, oil and applesauce. Pour the wet mixture into the dry ingredients and stir until combined. Fill the muffin cups evenly (there will be a good amount of batter, which makes for tall muffins). Sprinkle the tops with granulated sugar.