1 cup unsalted butter, softened to room temperature
1 ½ cups granulated sugar
1 large egg, room temperature
2 teaspoons vanilla extract
2 ½ cups all-purpose flour
1 teaspoon baking powder
½ teaspoon salt
1/2 cup unsalted butter (for frosting)
3 cups powdered sugar (for frosting)
2 tablespoons whole milk (for frosting)
1 teaspoon vanilla extract (for frosting)
Orange and purple gel food coloring
Halloween-themed sprinkles and candy eyes
Instructions
Preheat your oven to 350°F (175°C). Line a 9×9 inch square baking pan with parchment paper, leaving a slight overhang on the sides. This will make it much easier to lift the bars out of the pan once they are cooled and frosted.
In a large mixing bowl or the bowl of a stand mixer, cream together the softened butter and granulated sugar. Beat on medium-high speed for about 2-3 minutes until the mixture is light, fluffy, and pale in color.
Add the egg and vanilla extract to the butter mixture. Beat again until fully combined, scraping down the sides of the bowl with a spatula to ensure everything is incorporated evenly.
In a separate medium bowl, whisk together the flour, baking powder, and salt. Gradually add these dry ingredients to the wet mixture while mixing on low speed. Mix just until the flour disappears; do not overmix, as this can make the bars tough.
Press the cookie dough evenly into the bottom of your prepared baking pan. Bake for 20 to 23 minutes. The edges should be a very light golden brown, but the center should still look slightly soft. Do not overbake! Allow the bars to cool completely in the pan.
While the bars cool, make the frosting by beating the butter, powdered sugar, milk, and vanilla together until smooth. Divide the frosting and add your food coloring. Spread the frosting over the cooled cookie base, add your Halloween sprinkles and candy eyes, then slice into squares.