Lemon Sugar Cookie Bars

Ingredients

• 2 1/2 cups all-purpose flour
• 1 1/2 tsp baking powder
• 1/2 tsp salt
• 1 cup granulated sugar
• 1 Tbsp lemon zest
• 10 Tbsp unsalted butter, softened partially*
• 1 large egg
• 1 large egg white
• 2 Tbsp sour cream
• 1 tsp lemon extract
• 1 tsp vanilla extract
• 1/2 cup unsalted butter, softened
• 2 1/2 cups powdered sugar
• 2 tsp lemon zest
• 2 Tbsp fresh lemon juice
• Yellow food coloring and sprinkles )

Directions

1. For the bars, heat the oven to 375 degrees. Coat a 13" x 9" baking dish with butter and set it aside. In a mixing bowl, whisk the flour, baking powder and salt for 20 seconds, then put that bowl aside.
2. Place the sugar and lemon zest in the bowl of an electric stand mixer. Use your fingertips to work the zest into the sugar until it smells citrusy and takes on a faint yellow tint. Add the butter and beat the mixture until it looks light and fluffy. Mix in the egg, followed by the egg white. Add the sour cream, lemon extract and vanilla extract, and blend until everything comes together. Gradually add the dry ingredients and mix only until the dough is combined.
3. Coat your hands with non-stick cooking spray, or rub them with butter, then gently pat the dough into an even layer in the prepared baking dish. Bake until the bars are set and a toothpick poked into the middle comes out clean, about 15 – 16 minutes. Let them cool completely, then frost, add sprinkles and slice into squares.
4. For the frosting, beat the butter in the bowl of an electric stand mixer fitted with the paddle attachment until it is fluffy and light. Add the powdered sugar, lemon zest and lemon juice, and continue mixing until the frosting is airy and smooth. Add food coloring if you want a yellow tint.
5. The butter should still feel cool when you use it, which helps keep the dough from getting too warm and sticky while you press it into the pan.