01 -
Preheat oven to 175°C. Grease a 23 x 33 cm baking pan and line with parchment paper.
02 -
In a large bowl, beat together room-temperature butter, powdered sugar, and granulated sugar until light and fluffy.
03 -
Add eggs one at a time, mixing thoroughly after each addition. Stir in pure vanilla extract.
04 -
In a separate bowl, whisk together all-purpose flour, salt, and baking powder.
05 -
Gradually fold the dry ingredients into the butter mixture, mixing just until combined. Do not overmix.
06 -
Spread batter evenly into the prepared pan. Bake for 18–22 minutes, or until edges are lightly golden. Allow to cool completely in the pan.
07 -
In a medium bowl, beat butter until smooth. Gradually add powdered sugar, milk, and vanilla extract, mixing until creamy and spreadable.
08 -
Spread frosting over cooled cookie bars. Add sprinkles before frosting sets. Cut into 24 squares and serve.