Preheat Oven: Preheat to 325°F. Spray a 9×13-inch pan with non stick spray, and then line with parchment paper. This makes it easy for the parchment to stick to the pan when you spread the bars later on.

Cream Butter, Cream Cheese & Sugar: In a large mixing bowl or stand mixer fitted with the paddle attachment, beat the butter, cream cheese, and granulated sugar together on medium speed until light and creamy, about 2–3 minutes. Start Timer

Add Wet Ingredients: Mix in the egg, egg yolk, vanilla, and almond extract (if using) until smooth and well combined. Scrape down the sides of the bowl as needed.

Add Dry Ingredients: In a separate bowl, whisk together the flour, cornstarch, baking powder, salt, and baking soda. Gradually add to the wet ingredients on low speed until a soft dough forms. It will be pretty soft, and not like a normal dry-ish cookie dough texture. We want soft, that’s good!

Add sprinkles: Fold in the Christmas sprinkles.

Spread and Bake: Press the dough evenly into the prepared pan with an offset spatula. Bake for 25-30 minutes, or until the edges are lightly golden and the center looks just set. (It’s crucial for these bars to not overbake, they’ll continue to firm as they cool and we want them soft and chewy!) Start Timer

Cool: Allow bars to cool completely in the pan on a wire rack before frosting.

Make the Frosting: In a medium bowl, beat the butter until smooth. Add the vanilla, almond extract (if using), and salt. Gradually mix in the powdered sugar until combined, then add the heavy cream and beat for 1-2 minutes until light and fluffy. Tint with food coloring, if desired. (Example: A couple drops of red for a pretty pink color, or green for Christmas)

Frost & Decorate: Spread frosting evenly over cooled cookie bars and top with additional sprinkles. Slice into squares and enjoy!