01 - Preheat the oven to 350°F. Line an 8x8-inch baking pan with parchment paper, ensuring an overhang for easy removal.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, and salt until thoroughly blended.
03 - In a large bowl, whisk the melted butter, light brown sugar, and granulated sugar until the mixture is smooth.
04 - Add creamy peanut butter into the sugar mixture and mix until homogenous.
05 - Beat in the eggs one at a time, ensuring each is fully incorporated before mixing in the vanilla extract.
06 - Gently fold the dry ingredients into the wet mixture just until no streaks of flour remain; avoid overmixing.
07 - Fold in the toffee bits and semisweet chocolate chips, if desired.
08 - Spread the batter evenly into the prepared pan, smoothing the top for uniform baking.
09 - Bake for 23–27 minutes, or until the surface is golden and a toothpick inserted in the center yields a few moist crumbs.
10 - Allow to cool completely in the pan before lifting out using parchment overhang and cutting into squares.