Preheat the oven to 350° F and line a 9x13-inch pan with parchment paper or foil leaving an overhang on the sides. Coat with baking spray.
In a medium bowl whisk the flour, baking powder, and salt together.
In a separate large bowl whisk the melted butter and brown sugar together. Whisk in the eggs and vanilla until well combined.
Add the dry ingredients and mix gently just until combined.
Mix in the toffee and chocolate.
Scoop into the pan and spread out evenly. Sprinkle the top with a few chips/chunks if you like.
Bake 22 to 25 minutes until the edges are lightly browned and the center is set. Cool on a wire rack.
Lift to a cutting board and slice into squares or rectangles. Store leftovers tightly covered in a cool, dry place 3 - 4 days. They start to dry out after that.