Preheat your oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, allowing some overhang on the sides to lift the blondies out easily once baked.
In a large bowl, combine the smooth peanut butter, melted butter, and granulated sweetener. Use an electric mixer or whisk to blend until creamy and smooth. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
In a separate bowl, whisk together the almond flour and baking powder to distribute the leavening evenly.
Gradually fold the dry ingredients into the wet mixture using a spatula. Be gentle but thorough to avoid overmixing, which can toughen the blondies. The batter will be thick and slightly sticky.
Fold in the sugar-free chocolate chips or chopped dark chocolate until evenly distributed throughout the batter.
Spread the batter evenly in your prepared pan, smoothing the top with a spatula. Bake for 20-25 minutes, or until the edges are golden and a toothpick inserted into the center comes out with just a few moist crumbs. Do not overbake to keep them fudgy.
Allow the blondies to cool completely in the pan on a cooling rack before slicing. This helps them set up and makes cutting easier. Once cool, lift them out using the parchment paper and slice into squares.
