If you are looking for the perfect treat, this sourdough key lime cookies recipe is exactly what you need. The combination of tangy key lime juice and the subtle depth of sourdough discard creates an incredibly chewy and bright dessert. Not only is it a great way to use up your extra sourdough starter, but it also provides a unique flavor profile that rivals any nutritious citrus snack. These cookies are perfect for summer gatherings or when you need a little sunshine in your kitchen.
Table of Contents
Why you’ll love this sourdough key lime cookies recipe
- Perfect use of discard: A delicious and creative way to use up your sourdough discard without any waste.
- Bright and tangy: The fresh key lime juice and zest add a beautiful, zesty punch.
- Soft and chewy texture: Sourdough discard naturally makes the cookie texture incredibly tender and chewy.
- Quick and easy: The dough comes together in under 15 minutes, making it a hassle-free bake.
The simple ingredients you need
You only need a handful of basic pantry staples to make these vibrant cookies.
Unsalted Butter
Using unsalted butter allows you to control the exact amount of salt in the recipe. Make sure it is properly softened to room temperature for the best texture.
Granulated Sugar
Granulated sugar helps create the perfect chewy texture and slightly crisp edges while balancing the tartness of the lime.
Sourdough Discard
The star ingredient! Unfed sourdough discard adds moisture and a subtle tang that complements the citrus notes beautifully.
Fresh Key Lime Juice and Zest
Fresh is always best. The zest contains essential oils that provide a deep citrus flavor, while the juice adds the signature tartness.
Large Egg
Acts as a binder to hold the cookies together and adds richness.
All-Purpose Flour
A versatile base that gives the cookies their structure without making them too dense.
Baking Soda and Salt
Baking soda helps the cookies rise and spread, while salt enhances all the flavors.

How to make sourdough key lime cookies
- Preheat your oven: Set it to 350°F (175°C) and line a baking sheet with parchment paper.
- Cream the butter and sugar: In a large bowl, beat the softened butter and sugar until pale and fluffy.
- Mix in wet ingredients: Add the sourdough discard, egg, key lime juice, and zest. Beat until combined.
- Add dry ingredients: Whisk the flour, baking soda, and salt together, then gradually fold them into the wet mixture.
- Bake the cookies: Scoop 1-inch balls of dough onto the baking sheet and bake for 10-12 minutes until golden.

How To make Lime Glaze
To take these cookies to the next level, drizzle them with a simple, sweet, and tart lime glaze once they are completely cooled.
- Sift powdered sugar: Sift 1 cup of powdered sugar into a medium bowl to ensure a smooth glaze.
- Add lime juice: Whisk in 1 to 2 tablespoons of fresh key lime juice until you reach your desired consistency.
- Drizzle: Use a spoon or a small piping bag to drizzle the glaze generously over the cooled cookies. Let it set for about 15 minutes before serving.

Fun variations to try
If you want to switch things up, here are a few simple twists on the classic recipe. And if you love experimenting with cookie dough, be sure to check out our collection of 20+ Sourdough Cookies Recipes or our Ultimate Chocolate Chip Cookies guide!
Key Lime Crinkle Cookies
For a gorgeous, powdered sugar finish, roll your cookie dough balls lightly in granulated sugar followed by a generous coating of powdered sugar before baking. They will spread and crackle beautifully in the oven, giving you a picture-perfect look.
White Chocolate Chips
Fold in a half cup of white chocolate chips for a sweet, creamy contrast to the tart lime flavor.
Graham Cracker Coating
Roll the dough balls in crushed graham crackers before baking to mimic the taste of a key lime pie crust.
Coconut Flakes
Add a tropical twist by mixing a handful of shredded coconut into the batter.
Serving Ideas
These cookies are perfect on their own, but they pair wonderfully with a hot cup of tea or a cold glass of milk. For a true dessert experience, serve them alongside a scoop of vanilla bean ice cream, crumble them over a yogurt parfait, or serve them as part of a larger dessert spread featuring our Best Sourdough Dessert Recipes.

Prep and storage advice
Store these cookies in an airtight container at room temperature for up to 5 days. To keep them extra soft, you can place a slice of bread in the container to help retain moisture.
The dough can also be frozen! Simply roll the dough into balls, freeze them on a baking sheet, and transfer them to a freezer-safe bag. You can bake them straight from frozen, just add 1-2 extra minutes to the baking time.
FAQs
Can I use regular limes instead of key limes?
Yes! While key limes have a distinct, slightly floral tartness, regular Persian limes work perfectly as a substitute in this recipe.
Do I need an active sourdough starter or can I use discard?
This recipe specifically calls for sourdough discard. It doesn’t need to be active and bubbly since the baking soda provides the lift for the cookies.
Why did my cookies spread too much?
If your butter was too soft or melted, the cookies might spread. If your kitchen is warm, try chilling the dough for 30 minutes before baking.
We hope you enjoy baking and sharing these delicious sourdough key lime cookies. They are the perfect blend of tart and sweet, and we know they will quickly become a favorite in your recipe rotation!
