In a large mixing bowl add the softened butter, confectioners' sugar, and granulated sugar.
Cream together the butter, confectioners' sugar, and sugar until just combined.
Add the egg, vanilla extract, baking soda, cream of tartar, and 1 tablespoon of flour.
Combine the ingredients until smooth.
Add the flour to the wet ingredients.
Mix the flour until it is just incorporated into the cookie dough.
Cover your bowl with plastic cling film and chill the Christmas sugar cookie dough in the refrigerator for one hour.
Preheat your oven to 350 degrees F (175 degrees C) and line baking sheets with parchment paper.
Portion the cookie dough and roll into 1-inch dough balls. Place the dough onto your prepared baking sheets with 2 inches of spacing between each cookie. *For best results, return your readied cookie dough and the baking sheet to your refrigerator to chill between baking batches of cookies.
bake at 350 degrees F (175 degrees C) for 8-10 minutes, or until puffy and lightly golden on the cookie edges.
Remove from the oven and allow the cookies to cool for 5 minutes on the baking sheet before transferring cookies to a wire cooling rack to cool completely (before frosting). *For best results, allow your baking sheets to cool completely before readying the next batch of cookie dough.
Sugar Cookie Frosting & Holiday Sprinkles
Combine your holiday sprinkles in a small bowl to make your desired color mix. I'm using Wilton brand holiday jimmies, holiday nonpareils, and a gold mix pictured here.
Mix the frosting according to the instructions on the recipe here. I used butter flavored Crisco with lemon extract, for super white frosting use standard vegetable shortening (unflavored). *You can also use a buttercream frosting for the cookies.
You can spread the frosting onto the cookies, or pipe the frosting. Apply sprinkles by dropping them onto each cookie and pressing the sprinkles into the frosting. *Leave cookies on a wire cooling rack above a rimmed baking sheet to catch the extra sprinkles.You can also dip the frosted cookies directly into your sprinkle mix, and press down gently to set the sprinkles. The image below shows the piped frosting with applied sprinkles on the left, and the spatula-frosted cookie that was dipped into the sprinkles mix on the right.