01 - Preheat the oven to 350°F. Line an 8x8-inch baking pan with parchment paper, leaving a slight overhang for easy removal.
02 - In a medium mixing bowl, whisk together flour, baking powder, sea salt, and ground cinnamon. Set aside.
03 - In a large bowl, whisk the melted butter, packed brown sugar, and granulated sugar until fully combined and smooth.
04 - Add the egg and vanilla extract to the wet mixture, stirring until just combined.
05 - Stir apple butter into the wet ingredients until incorporated.
06 - Fold the dry ingredients into the wet ingredients using a spatula, just until no dry streaks remain. Avoid overmixing.
07 - Transfer batter to the prepared pan and spread evenly.
08 - In a small bowl, mix granulated sugar with ground cinnamon. Sprinkle the mixture evenly over the top of the batter.
09 - Bake for 28 to 32 minutes, or until the center is set and a toothpick inserted comes out with only a few moist crumbs attached.
10 - Allow the blondies to cool completely in the pan. Lift out using the parchment overhang and slice into 16 squares.