Preheat the oven to 350°F (175°C). Line a 9x13-inch baking dish with parchment paper, allowing some overhang for easy removal later.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, using an electric mixer, beat the softened butter and granulated sugar together until light and fluffy, about 3-4 minutes.
Add the egg, vanilla extract, and almond extract to the butter mixture and mix until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing until just incorporated. Do not overmix.
Spread the cookie dough evenly in the prepared baking dish. Bake in the preheated oven for 20-25 minutes, or until the edges are lightly golden and a toothpick inserted into the center comes out clean.
Allow the cookie bars to cool in the pan for about 10 minutes, then use the parchment overhang to lift them out and transfer to a wire rack to cool completely.
In the meantime, make the frosting by whisking together the powdered sugar and milk until smooth. If desired, add a few drops of food coloring to tint the frosting.
Once the cookie bars are completely cooled, spread the frosting evenly over the top.
Finish by sprinkling your choice of colorful sprinkles on top for a festive touch.
Cut into squares or rectangles and enjoy!
Notes
Use different food colorings for a fun and colorful frosting.