1-Step 1: Prepare Your Baking Equipment Start by preheating your oven to 350 degrees Fahrenheit. This temperature allows the bars to bake evenly without overbrowning the edges before the center is done. While the oven heats, line a 9″x9″ baking pan with parchment paper. Cut the parchment large enough so that it extends up two sides of the pan, creating handles that make removing the bars easier later. This simple step prevents sticking and allows you to lift the entire block out for clean, even cutting.

2-Step 2: Cream the Butter and Sugar In a large mixing bowl, beat together the softened butter and sugar until fluffy. This step is crucial for texture, so don’t rush it. When mixing the dough, make sure your butter is softened just right. Too cold and it won’t blend well, but don’t melt it or your bars won’t turn out chewy like you want. Beat for about 2-3 minutes until the mixture looks pale and fluffy. This incorporates air into the dough, contributing to that tender texture we’re after.

3-Step 3: Add Egg and Vanilla Beat in the egg and vanilla extract until fully incorporated. The mixture should look smooth and homogeneous at this stage. Scrape down the sides of the bowl to ensure everything combines evenly. The egg provides structure while the vanilla infuses the dough with that classic cookie flavor we all love.

4-Step 4: Incorporate Dry Ingredients Gradually beat in flour and baking powder until a thick dough forms. Add the dry ingredients in two or three additions rather than all at once. This prevents flour from flying out of the bowl and ensures even distribution. Mix only until the flour is just incorporated. Overmixing develops gluten and can result in tough, dense bars. The dough should come together cleanly and feel soft but not sticky.

5-Step 5: Fold in the Festive Sprinkles Gently stir in the festive sprinkles using a spatula or wooden spoon. Avoid using the electric mixer at this stage, as the spinning beaters can crush the sprinkles and create streaks of color in your dough. Fold until the sprinkles are evenly distributed throughout the dough. This creates those beautiful pops of color in every bite.

6-Step 6: Spread and Bake Spread the batter evenly in the prepared baking pan. Use a spatula or the back of a spoon to press the dough into an even layer, making sure it reaches all corners. For the most uniform results, use a pastry roller to spread the dough smoothly. Bake for 20 minutes or until the edges are lightly golden brown and a toothpick inserted in the center comes out clean.

7-Step 7: Cool Completely Allow the cookie bar to cool completely in the pan. This typically takes about 30-45 minutes at room temperature. Resist the urge to frost warm bars, as the heat will melt your frosting into a messy puddle. Once completely cool, lift the entire bar from the pan using the parchment paper handles. This makes frosting and cutting much easier.

8-Step 8: Prepare the Cream Cheese Frosting While the bars cool, prepare the frosting. In a mixing bowl, blend powdered sugar, softened butter, cream cheese, vanilla extract, and milk until smooth. The key here is ensuring both your butter and cream cheese are properly softened to room temperature. This prevents lumpy frosting and creates that silky, spreadable consistency. Start with 2 tablespoons of milk and add more if needed to reach your desired spreading consistency.

9-Step 9: Frost and Decorate Spread frosting generously over the cooled cookie bars using an offset spatula for the smoothest application. Work from the center outward, spreading to the edges. Top immediately with additional sprinkles while the frosting is still wet so they adhere properly. Be generous with those festive toppings!

10-Step 10: Cut and Serve Cut into squares using a sharp knife. For the cleanest cuts, wipe the knife blade with a damp cloth between each cut. Serve immediately for soft, creamy bars, or let the frosting set for 30 minutes at room temperature or in the refrigerator for a firmer texture. These bars are perfect on their own or paired with a glass of cold milk or hot cocoa.