These frosted sugar cookie cake bars are so dreamy! They taste just like classic frosted sugar cookies, but in chewy bar form.
Boy do I have an exciting recipe for you all today. These frosted sugar cookie cake bars are just so, so good. We take cookies (and cake) very seriously around here, so when I was developing this recipe, I had a whole checklist in my mind of what I wanted.
Extra soft yet chewy? Check. Deliciously sweet vanilla flavor? Check. A thick layer of buttercream frosting? Check. A super pretty and festive presentation? Check.
The cookie base was inspired by my s'mores bars. Those bars are made with more of a honey-flavored cookie base, similar to graham crackers, but I love the texture of those bars so I knew this recipe had to be an adaptation of that one.
And of course, the buttercream frosting really pulls it all together. You could skip it, or go for a thinner layer, but where's the fun in that? 😉
Why You'll Love These Sugar Cookie Cake Bars
- Just looking at them will put a smile on your face, surely? These would be perfect for a birthday party, and the best part is you can use any color for your frosting AND you can get creative with the sprinkles, too. They're easy to customize for any theme or holiday.
- If you love soft and thick sugar cookies, then you are going to be a huge fan of the texture.
- That buttercream frosting! It makes me think of birthday cake. What's not to love about that?
Ingredient Notes and Substitutions
- Gluten free flour blend: My favorite gluten free flour is Bob's Red Mill 1 to 1, hands down. You can use any blend as long as it contains xanthan gum. If you're not looking to make these bars gluten free, swap in all-purpose flour.
- Brown sugar: I really love using light brown sugar in this recipe, but you can go ahead and use dark brown sugar if that's what you have.
- Egg replacer: To make these cookie bars without eggs, we're using Bob's Red Mill Egg Replacer. Be sure to follow the instructions on the package. If you're not looking to make these bars eggless, you can use 1 egg instead.
- Powdered sugar: You can use any kind or brand of powdered sugar you like. Personally, I like baking with organic powdered sugar. No need to sift the sugar unless it's extra lumpy.
- Gel food coloring: I highly recommend using gel food coloring over liquid, as it's much more concentrated and a little bit goes a long way. This is my favorite set that I use all the time.
STEP ONE: Start by creaming the butter with both types of sugar. I love the flavor and texture that we get from incorporating light brown sugar.
STEP TWO: Add in the egg replacer and vanilla.
STEP THREE: Add your dry ingredients right in and mix on low speed.
STEP FOUR: Spread the dough evenly in a parchment-lined square baking pan. You may find it easier to just press it in with your hands. Bake on 350ºF for around 18 minutes, or until the edges are slightly golden.
STEP FIVE: Make the frosting. Beat the butter until creamy, then add in the powdered sugar, then the milk. You will want to add the milk in gradually, one tablespoon at a time, so you can properly judge how much you need.
- My #1 tip when it comes to baking (and especially gluten free baking) is to weigh your flour using a scale. This is the best way to ensure accuracy. We'll need 222 grams of flour for this recipe.
- For the frosting, you'll know when you have the consistency you want, but if you need to thin the frosting out more, add more milk. If you accidentally go too far, add another spoonful or two of powdered sugar.
- To achieve a pastel color, use a toothpick to grab just the tiniest amount of gel food coloring. And of course, you can use more or less food coloring than I did (or don't add any at all!).
- Make sure the sugar cookie bars have cooled completely before frosting.
Frequently Asked Questions
You'll know the bars are done when the edges are set and slightly golden.
Yes. To make these cookie bars dairy free, use your favorite non-dairy butter and milk.
I haven't tested it myself, but you should be able to naturally color the frosting. Here are some tips and ideas.
How To Store
You can store these sugar cookie cake bars in an airtight container at room temperature for 2 days. After that, be sure to move them into the refrigerator. They should keep for 5 days total.
Did you try my frosted sugar cookie cake bars? Leave me a comment below or tag me on Instagram @justastastyblog and #justastastyblog! And don't forget to subscribe to get new recipes directly in your inbox.
The Best Frosted Sugar Cookie Cake Bars
For the cookie bars:
- 1 ½ cups (222g) gluten free flour blend
- 1 ½ teaspoons baking powder
- ¼ teaspoon salt
- ½ cup (113g) unsalted butter room temperature
- ½ cup (100g) granulated sugar
- ½ cup (100g) light brown sugar packed
- 1 tablespoon Bob's Red Mill Egg Replacer mixed with 2 tablespoon water
- 1 teaspoon vanilla extract
For the buttercream frosting:
- ½ cup (113g) unsalted butter room temperature
- 1 ½ cups (180g) powdered sugar
- 1-2 tablespoons whole milk
- food coloring optional
- Preheat oven to 350°F. Line a square baking pan with parchment paper and set aside.
- In a small bowl, whisk the flour, baking powder, and salt together. Set aside.1 ½ cups (222g) gluten free flour blend, 1 ½ teaspoons baking powder, ¼ teaspoon salt
- Using a hand mixer or a stand mixer fitted with the paddle attachment, cream the butter with both sugars until combined. Add the egg replacer and vanilla extract and continue to beat.½ cup (113g) unsalted butter, ½ cup (100g) granulated sugar, ½ cup (100g) light brown sugar, 1 tablespoon Bob's Red Mill Egg Replacer, 1 teaspoon vanilla extract
- Add the dry ingredients and mix on low speed until combined. Pour into prepared pan and bake for 16-18 minutes, or until the edges are slightly browned. Allow to cool completely before removing from the pan.
To make the buttercream frosting:
- Using a hand mixer or a stand mixer fitted with the paddle attachment, beat the butter until smooth. Add in the powdered sugar and continue to mix until combined.½ cup (113g) unsalted butter, 1 ½ cups (180g) powdered sugar
- Add milk, one tablespoon at a time, and beat to achieve the desired consistency. Add gel food coloring, if using, and mix well. Spread frosting on cooled cookie base before slicing into bars.1-2 tablespoons whole milk, food coloring
- If you are not looking to make these bars gluten free, use all-purpose flour instead.
Be sure to follow the instructions on the package of Bob's Red Mill Egg Replacer. Once mixed with water, the egg replacer must sit for just a few minutes to thicken.
If you are not looking to replace eggs, you should be able to use 1 egg instead of the egg replacer.
- If you accidentally thin your frosting out too much with the milk, add more powdered sugar in, one tablespoon at a time.