01 - Preheat oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, ensuring an overhang for easy removal.
02 - In a medium bowl, whisk together the all-purpose flour, baking powder, and salt.
03 - In a large bowl, combine the melted butter and light brown sugar. Whisk until smooth. Incorporate the egg and vanilla extract, mixing thoroughly.
04 - Gently fold the dry ingredients into the wet mixture until just combined; avoid overmixing.
05 - Gently fold in half of the semisweet chocolate chips.
06 - Spread the batter evenly into the prepared baking pan.
07 - Drop spoonfuls of creamy peanut butter over the batter. Use a knife or skewer to swirl the peanut butter into the batter. Sprinkle the remaining chocolate chips over the top.
08 - Bake for 22–25 minutes, or until the edges are set and a toothpick inserted into the center emerges with a few moist crumbs.
09 - Allow the blondies to cool completely in the pan before lifting out using the parchment paper overhang and cutting into squares.