Valentine's Day Sugar Cookie Bars

For the cookie bars:
Preheat oven to 350 degrees F. Line an 8-inch or 9-inch square baking pan with aluminum foil, making sure to leave enough overhang on the sides. Set aside.

In a large bowl using a hand-held mixer or stand mixer fitted with a paddle attachment, cream the softened butter for about 1 minute on medium speed. Once smooth, add the sugar on medium speed until fluffy and light in color. Beat in egg, egg yolk, and vanilla. Scrape down the sides as needed.

In a medium bowl, whisk together the flour, salt, baking powder, baking soda, and cornstarch. With the mixer running on low speed, slowly add the dry ingredients to the wet ingredients in 3 different parts. The dough will be thick. Once combined, gently fold in 1/2 cup sprinkles using a rubber spatula (or by mixing on low speed).

Press the cookie dough evenly into the prepared baking pan. Bake for 25-26 minutes or until very lightly browned on top. You want the cookie bars to be extra soft, so careful not to overbake. Allow the bars to cool completely on a wire rack at room temperature before frosting. The center will sink slightly; this is normal.

For the frosting:
With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy - about 2 minutes. Add confectioners' sugar, cream, and vanilla extract with the mixer running on low. Increase to high speed and beat for 3 full minutes. Add more confectioners' sugar if frosting is too thin or more cream if frosting is too thick. Add a pinch of salt if frosting is too sweet. I usually add anywhere between 1/8 - 1/4 teaspoon of salt. Beat in food coloring at this phase, if using.

Remove cooled bars from the baking pan using the aluminum foil overhang on the sides. Frost the bars with a thick layer of frosting and decorate with extra sprinkles if desired. 

Cut into squares using a sharp knife. Store bars in an airtight container at room temperature for up to 2 days or in the refrigerator up to 5.

Room temperature egg and egg yolk preferred. Set out when you set out your butter to soften 1 hour ahead of time.

Cream or half-and-half is preferred for creamiest, fluffiest frosting. Keeping that in mind, milk would be an okay substitute if you do not have either on hand.

You can double this recipe and bake in a 9x13 pan for a larger batch of cookie bars. The bake time will increase to about 35 minutes.

Original recipe credit: Sally's Baking Addiction