Combine the flour, brown sugar, baking powder, pumpkin pie spice and salt together in a large bowl. Whisk them together thoroughly to aerate them. Separate the egg yolks in another bowl and the egg whites into their own separate bowl. Add the apple sauce, milk and vanilla to the bowl of egg yolks and whisk them all together until smooth.

Pour the wet ingredients into the dry ingredients and whisk it all together into a smooth batter. Take the egg whites that were set aside and whip them up with a hand mixer until they are like fluffy clouds. Use a spatula to gently fold them into the batter so that they don't deflate. Cover the bowl of batter and let it sit in the refrigerator overnight to rest. It also lets the flavor deepen!

In the morning, pre-heat an electric griddle to 300 degrees or a griddle pan over medium high heat on the stove. Lightly grease it with butter. Scoop the desired sized pancakes on in batches and let them cook for 4-5 minutes on the first side. Flip them over to puff up and cook on the second side for another 4-5 minutes. Then serve immediately with sliced apple and maple syrup!