Preheat your oven to 350°F (175°C). Grease or line your 8x8-inch baking pan with parchment paper, leaving an overhang for easy removal.
In a large bowl, cream together the butter (or coconut oil) and brown sugar until light and fluffy. Add the apple sauce, natural sweetener, egg, and vanilla extract. Mix until fully combined and smooth.
In a separate bowl, whisk together the flour, baking powder, ground cinnamon, and sea salt. Make sure the ingredients are evenly distributed.
Gradually add the dry ingredients into the wet mixture, alternating with the water, beginning and ending with the dry flour mixture. Stir until just combined; avoid overmixing to keep the blondies tender.
Gently fold in the dark or semi-sweet chocolate chunks, ensuring they are evenly spread throughout the batter.
Pour the batter into your prepared pan, smoothing the top with a spatula. Sprinkle a generous layer of cinnamon sugar over the surface to replicate that churro crunch. Bake for 25-30 minutes or until a toothpick inserted near the center comes out with just a few moist crumbs.
Allow the blondies to cool completely in the pan on a cooling rack. Once cool, use the parchment overhang to lift them out and cut into squares.
