Preheat the oven to 350 degrees Fahrenheit.
In a small dish, combine the sugar and cinnamon and set aside.
In a medium mixing bowl, whisk together the egg, sugar, apple sauce, melted butter and vanilla.
Add in the remaining ingredients, making sure to spoon and level the flour, don't scoop from the bag. Stir together with a wooden spoon until combined.
Add half of the batter to an 8x8 baking pan lined with parchment paper and spread evenly. Sprinkle on half of the cinnamon sugar mixture on top.
Add the rest of the batter on top, spreading evenly, but don't worry if it's not perfect. It helps to use a rubber spatula. Sprinkle on top the rest of the cinnamon sugar and use a toothpick to make swirls.
Bake for 21-28 minutes or until a toothpick comes out clean. Let cool completely before slicing,
Whisk together the ingredients for the glaze, then drizzle on top of the blondies once cool. Cut into 16 slices and enjoy!