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Closeup View of Buttercream Frosted GF Shortbread Cookie Bar

Buttercream Frosted GF Shortbread Cookie Bars

Stop the presses: BRING THESE COOKIES TO EVERY EVENT SAID EVERYONE! Seriously, these Buttercream Frosted GF Shortbread Cookie Bars are one for the books. Perfect for any event, the cookie base is dense, soft, and just slightly crumbly. The buttercream frosting has the perfectly added sweetness and richness. These bars are melt in your mouth perfection.

Sideview of Frosted Buttercream GF Cookie Bar on Plate
Sideview of Frosted Buttercream GF Cookie Bar on Plate [Haen, 6/22]

A Bar for Every Occassion

It’s no mistake we are releasing this amazing cookie bar recipe for the Fourth of July, but what I love most about them is that they can be suited to any occasion. You can add various colors, sprinkles, or even fruit toppings (great example of a fruit flag design on this site). These bars allow your artistic side to shine. For example, my daughter Charlotte loves pink, so for her, we used pink frosting and unicorn sprinkles. She was delighted! The bars were beautiful and she was able to help me decorate them. If you have young children in your household, these bars are the perfect “lil’ helper” project. Have the cookie base and frosting ready, line the entire house in plastic sheeting, and let the wildlings have fun frosting and decorating (I don’t actually line the house in plastic, but the idea sounds revolutionary).

Topside View of Decorated Buttercream Frosting
Topside View of Decorated Buttercream Frosting, [Haen, 6/22]

The Journey for the Perfect Texture

These bars are a staple in my household, but I usually bake them with wheat flour. Since starting the blog with my brother, I have become immersed in the world of gluten free baking! What I’ve realized is that 1-for-1 flour is great in many recipes and a flop in others. After countless trials to replicate the taste and texture of my beloved shortbread cookie bars, I was thinking the 1-for-1 was a flop. And then, like a fairy Godmother, my dear friend Stephanie intervened. Stephanie, being gluten free for many years, suggested a different ratio of flours than I was currently using, leading to the perfect replica. Her tips nailed it, the cookie base is just DELIGHTFUL; it’s buttery, rich, and crumbles at just the right time. It ticks all the boxes for an excellent shortbread bar. Yet, what is a shortbread bar without frosting?

Closeup Bite of Buttercream Frosted GF Shortbread Cookie Bar on Plate
Closeup Bite of Buttercream Frosted GF Shortbread Cookie Bar on Plate [Haen, 6/22]

Why Buttercream?

Continuing on, what is a shortbread cookie without frosting? And I mean REAL frosting, not the powdered sugar and milk stuff (although that type has its time and place). We’re talkin’ buttercream… 🙌

Buttercream made with exclusively butter is undeniably the best type of frosting the world over. When you use only butter, it literally melts in your mouth, because the melting temperature for butter is incredibly close to body temperature (thank you God for this small gift).

Giving credit where it’s due, I have adapted these Buttercream Frosted GF Shortbread Cookie Bars from the Busy Baker’s recipe here.

Side View of Entire Buttercream Frosted GF Shortbread Cookie Sheet
Side View of Entire Buttercream Frosted GF Shortbread Cookie Sheet [Haen, 6/22]


The hardest part about these bars is not eating all of them before the frosting sets…

But really, the hardest part in making these bars is the time period between baking and frosting (I’ve messed this one up before!). Otherwise it’s a walk in the park. You don’t need a stand mixer and you really only need one bowl. In the video, I walk you through the frosting technique (in case you want to use my same design for the fourth). They cut easily and come out of the pan like a dream. Difficulty level = easy. Pleasing level = high. Travel and sharing level = dependent on your generosity.

Table Setting of Cookie Bars and Milk [Haen, 6/22]

Tips and Tricks for Making Buttercream Frosted GF Shortbread Cookie Bars

  • For both frosting and cookie dough assembly, it’s important to have very soft butter. If you leave your butter out the night before making it, that usually works well (especially in summer months), but if your butter isn’t soft, check out the tips and tricks at Cafe Sucre Farine in this recipe. My aunt Chris has several suggestions that work great.
  • When I originally adapted this recipe, I used only 1:1 flour. The taste was great but the texture was not quite right. Tapioca flour is very fine and quite easy to find. It’s worth it for this recipe. If you cant find it, you can use 1/2 cup of corn starch as a replacement.
  • When mixing the frosting, the powered sugar is so fine it tends to fly in the air. Pro Tip: Put your bowl in your sink while mixing. Much of the mess will land back in the sink and make for an easy cleanup.
  • If you have a smaller group, you can cut this recipe in half and put it into a pie dish. It’s super cute and reminiscent of a cookie pie/cake.
  • If you aren’t gluten free and want to make these bars anyway, just replace the 1:1 and tapioca flour with white all purpose flour (2.5 cups), and bake at 375 for about 16 minutes (or until edges are starting to turn brown). Frosting is the same.
  • *This calls for full fat greek yogurt, but if you only have no fat, use that and 1 extra Tbsp of butter.
  • **If you don’t have heavy cream for the frosting, you can use milk.
  • ***I like a glass baking dish for this recipe because I think the cookie bars look quite beautiful in them. BUT, many bakers prefer metal pans and that can be used as well. Just decrease baking time by 2 minutes as it should heat up and cook faster. If you are interested in knowing more about the differences, check out this article here by Bon Appétit.
Closeup View of Buttercream Frosted GF Shortbread Cookie Bar
Closeup View of Buttercream Frosted GF Shortbread Cookie Bar [Haen, 6/22]

Buttercream Frosted GF Shortbread Cookie Bars

5.0 from 4 votes
Course: DessertDifficulty: Easy


Prep time


Cooking time


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  • Cookie Dough Base
  • 1/2 Cup Butter, Softened (1 stick)

  • 1 Cup White Granulated Sugar

  • 1 Tbsp Vanilla

  • 3 Tbsp Full Fat Greek Yogurt or Sour Cream *See tips and tricks

  • 1 Large Eggs

  • 1+1/2 Cups 1:1 Gluten Free Flour

  • 1 Cup Tapioca Flour

  • 1+1/2 tsp Baking Powder

  • 1/2 tsp Baking Soda

  • 1/4 tsp Salt

  • Buttercream Frosting
  • 1/2 Cup Butter (1 Stick)

  • 3 Cups Powdered Sugar

  • 1/2 Tbsp Vanilla

  • 2-6 Tbsp Heavy Cream **see tips and tricks


  • Preheat oven to 350 degrees and grease 9×13 glass baking dish (see tips and tricks ***).
  • Use a large mixing bowl and cream 1 stick of butter with 1 cup of white sugar. The mixture should be light and fluffy. Add 1 Tbsp vanilla and 3 Tbsp greek yogurt. Mix well, Add 1 large eggs and mix again.
  • Spread 1+1/2 cups 1:1 gluten free flour over wet ingredients. Next, spread 1 cup tapioca flour evenly over the bowl. Then, evenly distribute 1+1/2 tsp baking powder, 1/2 tsp baking soda, and 1/4 tsp salt over the top. Use a spoon to mix gently until partly combined, then use a hand mixer until ingredients are fully combined.
  • Pour dough into greased baking dish and gently pat until dough is equally spread across pan, place in middle rack of oven for 14-16 minutes or until the edges start to turn brown. When you slightly shake the pan, the cake should be mostly still (not wobbly). If cake is wobbly, check every 1 minute until done. Remove from oven and cool completely (2-4 hours)
  • Buttercream Frosting
  • Mix 3 Tbsp of heavy cream with 1/2 Tbsp of vanilla, set aside. Cream 1 stick of butter in large mixing bowl. Add 1 cup of powdered sugar and mix until creamy (about 4 minutes). Add 1 additional cup of powdered sugar and repeat the mixing process. Add the last and final cup of powdered sugar and mix until crumbly. Pour in vanilla/cream mixture and beat until entire frosting is creamy and spreadable (not pourable). If you aren’t getting the consistency you want, continue adding 1 Tbsp of heavy cream at a time and fully incorporate it. Frost cooled cookie bars and decorate as you please. Enjoy!
  • 4th of July Decor
  • ***This entire process is in our video***
  • Create a single column using 10-12 drops of red food coloring. Using a butter knife, smear coloring from side to side to create a 1 inch column. Leave a 1-inch white frosted section clear. Create a new single column using 10-12 drops of navy blue food coloring. Repeat until you have red, white and blue columns across the entire cookie sheet.
  • Using a fork, use mini side to side motions to smear the columns in a perpendicular manner. Drag the fork across the entire cookie sheet, smearing the columns in mini zig-zag patterns until it looks tie-died.

Recipe Video


  • If you want to non-gluten free recipe, check out the tips & tricks section

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  1. Nice post. I learn something totally new and challenging on websites I stumbleupon on a daily basis. It will always be interesting to read through content from other writers and use something from their websites.

  2. These sound wonderful and look SO festive, I can’t wait to try them 🥰

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