Preheat your oven to 350°F (175°C) and line your baking pan with parchment paper for easy removal.
In a mixing bowl, combine the melted butter (or coconut oil), lightly beaten egg, and vanilla extract. Whisk until well blended.
In another bowl, mix together the almond flour, sugar-free brown sugar, baking powder, ground cinnamon, baking soda, and sea salt. Stir until evenly distributed.
Gradually add the dry mixture to the wet ingredients, stirring until combined. Be careful not to overmix; just blend until you see no dry flour.
Pour the batter into the lined baking pan, spreading it evenly. In a small bowl, mix the sugar-free granulated sweetener with the additional ground cinnamon, then sprinkle evenly over the top of the batter.
Bake in the preheated oven for about 20-25 minutes, or until the edges are lightly browned and a toothpick inserted in the center comes out clean.
Allow the cookie bars to cool in the pan for about 10 minutes before transferring them to a wire rack to cool completely. Once cooled, cut into squares and enjoy!