Easy and Decadent Halloween Sugar Cookie Bars

These soft, decadent Halloween sugar cookie bars are easier to frost than a cake and will seriously impress all your friends looking for a treat rather than a trick.

The sugar cookie base is soft with the perfect amount of vanilla. To decorate, simply top with buttercream frosting and fun sprinkles of your choosing.

These Halloween sugar cookie bars can serve quite a bit of people too, perfect for parties. Dice them into traditional bars for less guests or smaller squares to feed a crowd. Either way, you’ve served everyone’s new favorite treat.

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How to Make The Best Halloween Sugar Cookie Bars

Using the Right Buttercream

You may already know this, but refrigerating sugar cookies can really dry them out, which we obviously want to avoid. But, topping sugar cookie bars with delicious, soft, vanilla buttercream frosting would usually need to be refrigerated.

So there seems to be a dilemma.

But, not so fast. If we use a crusting buttercream, we can store our delicious Halloween sugar cookie bars on the table the entire Halloween celebration, plus a few days! Not that you’re likely to have any leftovers…

That said, what is this crusting buttercream? Well, crusting buttercream is a buttercream that has more sugar than usual which will act like a preservative. Cool, huh?

Now you may be thinking, buttercream is so sweet, how can I handle more sugar in my frosting? This is easy, the sugar cookie bars are much, much thicker than sugar cookies, making it almost necessary to add a bit more sugar in the frosting.

It is in no way going to be too sweet! You’ll love these.

Making the Halloween Sugar Cookie Bars

Preheat the oven to 350 degrees Fahrenheit.

In a medium sized mixing bowl, combine three cups of all-purpose flour and two teaspoons of baking powder.

Make sure to use baking powder, as baking soda will cause the cookies to rise and they already come out thick in this recipe.

Cube one cup of cold, salted butter and add it to your stand mixer. Pour in one cup of granulated white sugar and then cream the sugar and butter together using the paddle attachment.

Add in one egg and one and a half teaspoons of vanilla extract. Beat these ingredients into the creamed butter/sugar mixture until combined.

Slowly add in the flour and baking powder mixture into the stand mixer bowl until everything is combined into a ball.

Line an 8×8″ pan with parchment paper and then press the dough into the pan. I found it best to hold all the dough in my hands and then flatten it out into a square shape similar to the size of the pan. Then, continue pressing the dough into the pan until the dough is relatively even in height.

Bake the sugar cookie dough for 30-35 minutes. You will know when it is done when the top is no longer wet looking and slightly golden. Try not to overbake, as the edges of the dough will get hard. But hey, some people love crispy edges so it’s up to you!

Allow the baked sugar cookie to cool completely before lifting it out of the pan with the parchment paper and frosting it.

Making the Crusting Buttercream Frosting

In a stand mixer with the paddle attachment, whip one half cup of room temperature unsalted butter until light and fluffy. One half cup of butter is equivalent to one stick of butter or 8 tablespoons.

Once light and fluffy and all of the lumps are gone, mix in two cups of powdered confectioner’s sugar, one teaspoon of vanilla extract, and one tablespoon of whole milk.

Mix everything on low speed until the powdered sugar is mostly mixed in to the butter. Do not turn the mixer higher than low. If needed, use a rubber spatula to stir the frosting.

Overmixing buttercream can cause air bubbles. If you do overmix, here’s a post on how to fix it. I promise it’s not terribly hard to fix, but, as always, prevention is better.

Once the frosting is mixed, stir in your desired gel food dye if using colored frosting. This time I chose to go with a light purple.

Cover the frosting with plastic wrap and set this aside until the sugar cookie bars are completely cooled from the oven. The color will continue to develop and the powdered sugar will continue to blend in with the butter for the perfect taste and consistency.

If you aren’t frosting the Halloween sugar cookie bars today, keep the buttercream in an airtight container in the refrigerator for up to a week or the freezer for up to three months.

Frosting the Halloween Sugar Cookie Bars

Once the cookie bar is completely cooled and removed from the pan, frost the cookie base with the buttercream.

If adding sprinkles, be sure to add them immediately after frosting so that they stick to the buttercream before the buttercream crusts.

I recommend waiting 8 hours before cutting into these sugar cookie bars. I know, it’s a long time but it is worth it!

Waiting until the frosting crusts will not only make for cleaner cuts, the sugar cookie bars will also be more moist. The buttercream frosting will seep into the cookie layer during the crusting process, resulting in a softer bite.

I prefer to cut mine into 1″x1″ squares since the cookie layer is so thick. I also find this size is more approachable to any party guests, especially on an event like Halloween when so many other sweets are typically present.

Halloween Sugar Cookie Bars

These Halloween sugar cookie bars are the perfect mix between a cookie and a cake. Topped with a kid & adult approved buttercream frosting, these bars are soft and have the perfect amount of sweetness.

Print Pin Rate

Course: Dessert

Cuisine: American

Keyword: All American Buttercream Frosting, Buttercream Cookie, Halloween Sugar Cookie Bars, Sugar Cookie Bars

Prep Time: 1 hour hour

Cook Time: 30 minutes minutes

Total Time: 1 hour hour 30 minutes minutes

Servings: 30 one inch square bars

Author: Leah Buehler

Equipment

• Stand Mixer with a Paddle Attachment
• Rubber Spatula
• Medium Sized Mixing Bowl
• Measuring Cups & Spoons
• 8x8" Pan
• Plastic Wrap

Ingredients

Soft Sugar Cookie

• 3 cups all purpose flour, plus more for rolling 284 grams
• 2 tsp. baking powder
• 1 cup cold salted butter cut into cubes
• 1 cup granulated white sugar
• 1 egg
• 1.5 tsp. vanilla extract add up to a tablespoon

Vanilla Buttercream Frosting

• ½ cup room temperature unsalted butter
• 2 cups powdered sugar confectioner's sugar
• 1 tbsp. milk whole milk is best
• 1 tsp. vanilla extract
• gel food dye optional
• sprinkles optional

Instructions

• While you will make the cookies first, you will want to set the unsalted butter out so that it comes to room temperature. The unsalted butter will be used when preparing the buttercream.

Soft Sugar Cookies

• Preheat the oven to 350 degrees Fahrenheit.
• In a medium sized mixing bowl, add in the flour and baking powder. Stir the ingredients to combine them.
• In the stand mixer, cream the salted butter and sugar together until all of the butter lumps are gone.
• Add in the egg and vanilla extract and mix until just combined.
• Slowly add the flour and baking powder mixture into the wet ingredients until the dough forms a ball. If the ball is very sticky, add another tablespoon of flour.
• Press the dough into a parchment paper lined 8x8" baking dish and bake for 30-35 minutes. The cookie is done when the top of the cookie doesn't look wet and is slightly golden in color.
• Allow the cookie to cool completely before removing from the pan and frosting it.

Vanilla Buttercream Frosting

• Add the room temperature unsalted butter to the stand mixer and mix with the paddle attachment until lighter in color.
• Add the powdered sugar to the mixer, along with the vanilla extract and milk.
• Place a clean towel over the stand mixer and mix on low speed until the sugar is incorporated. Use a rubber spatula to scrape the sides if needed.
• If adding gel food dye, mix the color in on low speed until fully incorporated. Cover the bowl with plastic wrap until the sugar cookie has completely cooled.

Decorating the Halloween Sugar Cookie Bars

• Remove the cookie bar from the pan. It will come out easily thanks to the parchment paper.
• Frost the cookie bar with the prepared buttercream frosting in an even layer. Add sprinkles immediately after frosting, before the frosting has a chance to crust.
• Allow the buttercream frosting to form a crust for 8 hours before cutting into the bars for a cleaner cut.

Notes

I recommend waiting 8 hours before cutting into these sugar cookie bars. I know, it's a long time but it is worth it!

Waiting until the frosting crusts will not only make for cleaner cuts, the sugar cookie bars will also be more moist. The buttercream frosting will seep into the cookie layer during the crusting process, resulting in a softer bite.

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