Preheat & Prepare: Preheat oven to 350°F. Grease a 9x13-inch baking pan with non-stick cooking spray or line it with parchment paper.
Cream Butter & Sugars: In a large mixing bowl, beat together the butter, granulated sugar, and brown sugar with an electric mixer until light and fluffy.
Add Wet Ingredients: Mix in the peanut butter, egg, and vanilla extract until well combined.
Combine Dry Ingredients: In a separate bowl, whisk together flour, baking soda, baking powder, and salt. Gradually mix into the wet ingredients until just combined.
Fold in Chocolate Chips: Gently fold in chocolate chips until evenly distributed.
Spread & Bake: Scoop the dough into the prepared pan and spread it evenly edge to edge. Bake for 20-25 minutes, or until golden brown and a toothpick inserted in the center comes out clean.
Cool & Add Hershey’s Kisses: Let the bars cool in the pan for 10 minutes, then cut into 24 bars. Press an unwrapped Hershey’s Kiss into the center of each bar.
Serve & Store: Enjoy warm or allow to cool completely. Store in an airtight container at room temperature for up to 5 days or freeze for up to 3 months.