Sourdough Sugar Cookie Bars

Sometimes you just need something sweet, even better if it has sprinkles. Enter these sourdough sugar cookie bars! These are such an easy dessert or fun way to share sugar cookies in a bar form. Perfect when you don't have time to cut out a heap of cookies individually, or you just want to layer on that delicious frosting!

Why You'll Love This Recipe!

The Frosting - ok so I know I'm all about the sourdough, but seriously the frosting on this recipe is next level good, especially if you use fresh strawberries for color and flavor. Trust me, it's the BEST! I show you exactly how to do it in this recipe!

Fun Way To Bake Cookies - this recipe is based on my sourdough sugar cookie recipe and is just an alternative way to bake them if you'd prefer not to have to roll them out and cut them into shapes. No rolling pin required!

Ferment the Cookie Dough - just like the cut out and decorate sugar cookies, you can ferment these sourdough sugar cookie bars in the fridge overnight if you'd like to. I've added instructions on how to do this further down.

Ingredients

• All Purpose Flour - there's no need for bread flour here, basic all purpose flour is perfect for these as you don't want too much gluten development to keep these soft and velvety.
• Baking Powder - just like a brownie, you don't want too much baking powder because you only want a little lift to give these that cookie dough texture.
• Salt - to cut through the texture in both the sourdough sugar cookie dough and the frosting.
• Sugar - granulated sugar for the cookie dough and powdered sugar for the frosting is what you'll need here.
• Room Temperature Butter - soft butter is used in both the cookie bar dough and the frosting. As always I've used salted, but feel free to use unsalted.
• Egg - I've used an extra large egg (mine was 75g). If your eggs are smaller, please use 2.
• Vanilla Extract - provides a delicious vanilla flavor to the cookie bars and frosting. You can use almond extract in the bars if you prefer.
• Sourdough Starter - you can choose to use active sourdough starter or sourdough starter discard for this recipe. Just be mindful that if you're using discard, you don't want it to be old and sour because it will impart these bars with an unpleasant flavor. Keep it to just a few days old if you can!
• Cornstarch - just a little bit of cornstarch helps to give these sugar cookie bars their soft, velvety texture.
• Heavy Cream - this helps to whip the frosting into the creamiest frosting you've ever had (seriously you are going to want to put this frosting on everything from now on).
• Strawberries - I've used 2 strawberries to color and flavor the frosting for the sourdough sugar cookie bars. It's an absolute game changer! You can leave the strawberries out if you'd prefer a plain vanilla frosting.
• Sprinkles - I've added these for a little fun to finish these off, you don't have to add them if you'd prefer not to.

How To Make Sourdough Sugar Cookie Bars

Preheat the oven to 180C (350F) and line a 9" x 9" pan with parchment paper. Set this aside.

Add all purpose flour, baking powder, cornstarch and salt to a mixing bowl and whisk together until well combined. Set this aside.

Add the butter and sugar to a mixing bowl and cream them together using a hand mixer until they are light and creamy (you could also do this in a stand mixer if you prefer).

Add the egg, vanilla extract and sourdough starter to the butter and sugar mixture and beat on medium speed until well combined.

Now, add the wet ingredients mixture to the dry ingredient mixture and combine into a soft dough (use low speed on hand mixer or stand mixer or wooden spoon). Don't over mix the dough, it needs to just come together.

Place the mixture into your baking pan, lightly pressing down to ensure it is smoothed out to the edges.

Bake the sourdough sugar cookie bars for around 30 minutes at 180C (350F) or until the edges are lightly golden.

Remove from the oven and allow to cool in the pan completely. While the cookie bars are cooling, prepare the frosting.

Make The Frosting

To the bowl of your stand mixer, add the butter, powdered sugar, heavy cream, salt and vanilla. Whisk on speed 3 to 4 until it comes together (it will be very stiff).

While the frosting is whisking, cut the strawberries up into small pieces and sprinkle a little powdered sugar over the top. Use a fork to mash it up so that it starts to liquefy. Once the juice has been released and it's fairly mashed up, it's ready to use!

Stop your stand mixer and swap over to the paddle attachment. Add the strawberries you just mashed up and whip the frosting until it's light and fluffy. I generally use speed 5 to 6 for this. It takes around 5 minutes for the frosting to be sufficiently whipped to perfection!

Once your sourdough cookie bars are cook, top them with the pink frosting and sprinkles. Allow the frosting to set before slicing into bars.

If you want to eat them straight away, slice them into bars with no delay! If you are wanting them to look a little more "perfect" then I recommend setting the frosting in the fridge to make slicing them much easier. My kids don't really care what these look like, they love all the frosting smudges, but if you want perfect frosting, a little time in the fridge definitely makes all the difference!

Just as a side note, this frosting is all kinds of amazing and is a delicious alternative to the cream cheese frosting I have listed in my sourdough strawberry rolls recipe.

Pan Size

The sourdough sugar cookie bars you can see in this post have been baked in a 9" x 9" square pan and topped with a large batch of frosting (the whole amount listed in the recipe card). If you don't want as much frosting, I recommend you halve the frosting amount or use the other half for something else - maybe these sourdough vanilla cupcakes.

You can also bake this recipe in a pan measuring 8" x 12" if you would prefer the cookie bars to be slightly thinner. The bake time should be the same, just keep an eye on the edges! The amount of frosting listed in the recipe is perfect for this size pan too.

Fermenting Overnight

You can ferment these sourdough sugar cookie bars overnight very easily! All you need to do is make the sugar cookie dough as per the instructions. When you get to step 6, instead of moving onto step 7 and placing into the oven, cover the dough in the pan and place into the fridge for up to 24 hours instead.

When you're ready to bake, preheat the oven and then place the cold dough straight from the fridge into the oven. Fermenting the dough and then placing it cold in the oven also helps to create a more chewy texture for these sourdough sugar cookie bars too!

How To Store + Freeze

Once sliced into squares I recommend storing these sourdough sugar cookie bars in an airtight container or cookie tin. The frosting will stay set better in a tin at room temperature than a plastic container. It tends to sweat in plastic.

They can also be stored in the fridge for up to 7 days, just allow them to come to room temperature before serving.

These freeze well, although I recommend freezing the baked cookie bars prior to frosting and cutting. So bake and cool and place into a ziploc bag and freeze. Thaw at room temperature before frosting and cutting into squares.

Share the sourdough love!