Preheat oven to 375 degrees Fahrenheit. Line a square 8 by 8-inch pan with parchment paper and set aside.
Make the Cookie Dough: Using a hand mixer or a stand mixer fitted with the paddle attachment, cream the butter and sugar together until smooth and a slightly lighter shade of yellow (about three minutes).Mix in the egg, vanilla extract, and almond extract until uniform, pausing to scrape down the sides of the bowl as needed to make sure everything is fully incorporated. 9 tablespoons unsalted butter, 1 cup granulated sugar, 1 egg, 2 teaspoons vanilla extract, 1 teaspoon almond extract
Meanwhile, in a mixing bowl, whisk together flour, baking soda, baking powder, salt, sprinkles and crushed peppermint.
2 ¼ cup all-purpose flour, ¾ teaspoon baking soda, ¾ teaspoon baking powder, ¾ teaspoon fine sea salt, ½ cup red and green jimmies sprinkles, ½ cup crushed peppermint candy
Add half the flour mixture to the wet mixture, and continue beating until combined, then repeat with the remaining flour until a dough forms.
Bake the Cookie Bars: Spread the dough into prepared baking pan in an even layer about on inch thick.I find it easiest to scoop and drop the cookie dough into the pan, then press and spread the drops of dough together into one piece. Transfer pan to oven to bake for 17-20 minutes or until the top is lightly golden brown. Cool the cookie bar completely in the pan before removing.As th bar cools, it will sink a bit in th middle and the edges will pull away from th pan. This is normal. Make the Frosting: While the cookie bar cools, use a hand mixer or stand mixer fitted with the paddle attachment to beat together the cream cheese, butter, powdered sugar, vanilla extract, salt, and food coloring, if using, until smooth (about three minutes).
2 ½ cups powdered sugar, 4 ounces cream cheese frosting, 2 tablespoons unsalted butter, 1 teaspoon vanilla extract, ¼ teaspoon fine sea salt, red or green food coloring
Cut and Decorate: Spread frosting over top of cooled cookie in an even, thick layer, then use a sharp knife to cut the bar into 16 squares. Add sprinkles and any other decorations you like.