Sourdough Sugar Cookie Bars

These sourdough sugar cookie bars are the perfect shortcut when you’re craving classic sugar cookies but don’t have time to roll and cut individual shapes. Made with sourdough discard, these soft and chewy bars are topped with a luscious frosting and festive sprinkles, making them an easy dessert for birthdays, holidays, and everyday baking.

Why You’ll Love This Recipe!

Soft, Tender Crumb – These sourdough sugar cookie bars bake up soft and tender with no crispy edges. You’ll love how velvety smooth they are!

The Buttercream 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! 

Easy 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! You might also like these sourdough chocolate chip cookie bars!

Ferment the Cookie Dough – 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. This really does create the best texture!

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.
• Butter – Butter softened at room temperature is used in both the cookie bar dough and the frosting. As always I’ve used salted butter, but feel free to use unsalted butter if you prefer.
• 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

You’ll start by adding the all-purpose flour, baking powder, cornstarch and salt to a large bowl and whisk together until well combined. Set this aside.

Now, to the bowl of a stand mixer, add the butter and sugar and whisk until they are light and creamy. Add the egg, vanilla extract and sourdough starter to the butter mixture and whisk on medium speed until well combined.

I recommend swapping to the paddle attachment before adding the wet ingredients mixture to the dry ingredients and combining into a soft dough. Don’t over mix the dough, it needs to just come together. You can also just use a spatula to do this step.

Place the mixture into a prepared 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 180ºC (350ºF) 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 buttercream frosting.

Make the Buttercream Frosting

To the bowl of a stand mixer fitted with a whisk attachment, 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!

Add the strawberries you just mashed up to the frosting and continue whipping it 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! Honestly, it’s worth spending the time here to ensure you get the right texture.

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

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.

Using A Different 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, it will just be slightly thinner.

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 an airtight container and freeze. Thaw at room temperature before frosting and cutting into squares.

Frequently Asked Questions

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