01 - Preheat the oven to 350°F. Line a 9x13-inch baking pan with parchment paper, leaving an overhang for easy removal.
02 - In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
03 - In a large bowl, whisk the melted butter, brown sugar, and granulated sugar until smooth. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
04 - Gradually fold the dry ingredients into the wet mixture until just combined—do not overmix.
05 - Gently fold in the chocolate chips and toffee bits, reserving a handful of each for topping if desired.
06 - Spread the dough evenly into the prepared pan. Sprinkle the reserved chocolate chips and toffee bits on top.
07 - Bake for 22–25 minutes, or until the top is golden brown and a toothpick inserted in the center comes out with a few moist crumbs.
08 - Let cool completely in the pan on a wire rack. Lift the bars out using the parchment overhang, then cut into 16 squares.