• Preheat the oven to 350°F
• Grease and line a 13x9 baking dish with parchment paper. Leave two sides hanging over for easy removal.
• Combine the unsalted butter and cream cheese together in a mixing bowl.
• Beat the granulated sugar until creamy.
• Beat in 1 egg and the vanilla extract.
• Beat in the salt and all-purpose flour until soft dough forms.
• If needed, knead with hands to combine the dough well.
• Place the cookie dough inside the baking dish and spread evenly across the dish. (To make this easier, place parchment paper on top of the dough and use a glass to spread the dough from the center of the dish to the edges.
• Make sure that the dough is evenly spread inside the dish before baking.
• Bake for 35-40 minutes. The edges should be lightly browned and the center set. If desired, bake for a few minutes extra at a time if you want firmer sugar cookie bars.
• Remove from the oven and allow to cool for 1 hour before frosting.

Sugar Cookie Frosting

• Beat the unsalted butter until creamy.
• Add in the lemon juice, milk, vanilla extract, and salt.
• Slowly beat in the confectioner's sugar.
• Add the desired amount of food coloring if using and blend well.
• Using an icing spatula, evenly spread the frosting and decorate with sprinkles if desired.
• Allow the frosting to harden before cutting into bars.
• Store in an airtight container.