Love Do-si-Dos®? You don’t need to wait until spring to satisfy your craving for these melt-in-your-mouth peanut butter cookies. These Sourdough Peanut Butter Oatmeal Sandwich Cookies are rich, buttery and so nostalgic. Sourdough discard adds a tangy twist to these homemade Girl Scout cookies.
Mimi is back with another incredible cookie! This is the fifth recipe in our collection, and this time, she drew inspiration from Dos-Si-Dos—classic peanut butter and oatmeal shortbread cookies filled with a sweet peanut butter filling. These cookies have a rich, nutty flavor and a delicately crisp texture. I couldn’t stop snacking on them and was genuinely surprised I had enough left to photograph!
One of the best parts of our collaboration is the opportunity to test and refine each recipe before sharing it! Check out our other cookie recipes, Sourdough Red Velvet Cookies, Sourdough Cranberry Biscotti, Sourdough Molasses Cookies, Sourdough Jam Thumbprints and Sourdough Chocolate Shortbread Cookies.
Why I love this recipe
- Makes crisp, melt-in-your mouth peanut butter sourdough shortbread cookies.
- Great way to use excess sourdough starter.
- Sourdough discard balances the nutty sweetness of the cookies and filling.
- Nostalgic favorite made from scratch with simple ingredients.
Ingredients and substitutions
- All-purpose flour: The low protein content of all-purpose flour imparts a crisp, delicate texture to these cookies. Do not substitute another type of flour in this recipe. If you need help figuring out which flour to use in your recipes, check out my post on, The Best Flour for Sourdough.
- Sourdough discard: Both active starter and sourdough discard work for this recipe. If you don’t have a sourdough starter, add 21 grams flour and 21 grams water to your dough.
- Peanut butter: Just like my Chewy Peanut Butter Sourdough Cookies, it’s important to use creamy peanut butter for this recipe since crunchy or natural will cause your cookies to fall apart.
- Old-fashioned oats: This recipe was developed and tested using old-fashioned oats, do not attempt this recipe using quick oats.
- See recipe card for detailed ingredient information.
Step-By-Step Instructions
Step 1: Make the cookie dough
Cream the butter, vanilla and sugar using a hand mixer or stand mixer. Add in the remaining ingredients until a stiff dough forms.
Step 2: Chill the cookie dough
Turn the dough out on a piece of plastic wrap. Roll the dough into a 15-inch log. Chill the dough for 4 hours or overnight.
Patience is a virtue
Don't skip the chill period! The butter needs to cool down before baking, otherwise your shortbread cookies will spread while they bake.
Step 3: Bake the shortbread cookies
Divide the dough into 44 portions. Arrange the cookies on a baking sheet at least an apart (your shortbread cookies will spread a little as they bake).
Step 4: Assemble the sandwich cookies
Make the filling and transfer to a piping bag. Turn half of the cookies upside down, pipe dollops of frosting onto the top of the turned over cookies and sandwich them together.
Baker's Tips
- Weigh your ingredients. Measuring by weight is much more accurate than by volume (with tablespoons and cups).
- Both sourdough discard and active sourdough starter will work for this recipe.
- This recipe was originally developed using salted butter, if you’d like to use that omit the salt from this recipe.
- Watch your cookies closely while they bake or they may brown too quickly.
- Let your cookies cool completely before frosting or your filling will melt.
Recipe FAQs
Sourdough discard is any portion of your starter removed during the feeding process or any part not used to leaven sourdough bread. You can use it in other bakes and dishes or store it in the refrigerator.
You can use active sourdough starter or just add 21 grams of flour and 21 grams of water or milk to your shortbread dough.
This recipe was developed and tested using creamy peanut butter. Your cookies may fall apart if you use natural peanut butter.
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Sourdough Peanut Butter Oatmeal Sandwich Cookies
Equipment
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Ingredients
Dough
- 226 grams unsalted butter softened
- 113 grams light brown sugar
- 2 teaspoons vanilla extract
- 57 grams peanut butter
- 43 grams sourdough discard
- 255 grams all purpose flour
- ½ teaspoon salt
- 50 grams rolled oats
Filling
- 113 grams unsalted butter softened
- 226 grams powdered sugar sifted
- 57 grams peanut butter
- ½ teaspoon vanilla extract
- ¼ teaspoon salt
- 14 grams milk up to 28 grams
Click US Customary to view volume measurements
Instructions
- Make the dough: In the bowl of a stand mixer fitted with the paddle attachment, add the butter, brown sugar, and vanilla extract. Mix on low until combined and there are no butter chunks.226 grams unsalted butter, 113 grams light brown sugar, 2 teaspoons vanilla extract
- Add in the sourdough discard, peanut butter, flour, salt and oats and mix to combine into a stiff cookie dough.57 grams peanut butter, 43 grams sourdough discard, 255 grams all purpose flour, ½ teaspoon salt, 50 grams rolled oats
- Chill the dough: On a large piece of plastic wrap, turn out the dough and form into a log that is about 15-inches long. Wrap tightly in plastic wrap and refrigerate for at least 4 hours or overnight.
- Prep: Preheat the oven to 350°F. Line two baking sheets with parchment paper.
- Remove the dough from the fridge and cut the log into 44 cookies that are about ¼-inch thick. Place on the prepared baking sheets. Poke the tops of the cookies with a fork a couple times.
- Bake: Bake for 22 to 24 minutes or until golden brown around the edges. Allow the cookies to cool completely on the baking sheets. Then turn over every other cookie and pair them together.
- Make the filling: In the bowl of a stand mixer fitted with the paddle attachment, add the butter, powdered sugar, peanut butter, vanilla, salt and milk as needed. Mix until combined and then speed mixer up to high and mix for 1 to 2 minutes or until light and fluffy.113 grams unsalted butter, 226 grams powdered sugar, 57 grams peanut butter, ½ teaspoon vanilla extract, ¼ teaspoon salt, 14 grams milk
- Assemble the cookies: Transfer the filling to a piping bag and cut a hole. Pipe dollops of frosting onto the top of the turned over cookies and sandwich them together.
- Store in a cool, dry place for up to 5 days.
- High Altitude — Bake at 350°F for 20 to 22 minutes or until golden brown around the edges.
Tips
These recipes were developed and tested using grams for precise measurements. To increase your chances of success, I recommend investing in a kitchen scale. I've included rough volume estimates (in tablespoons and cups), but they might not be totally accurate.
Remember all ovens are unique, these recipes were tested in my oven which runs cooler than others. You might need to lower the temperature if your bake appears to be browning too quickly. Monitor your bake closely and make adjustments if needed.
Notes
- Both sourdough discard and active sourdough starter will work for this recipe.
- If you don't have a sourdough starter, simply add 21 grams of flour and 21 grams of water or milk to your cookie dough.
- This recipe was originally developed using salted butter, if you’d like to use that omit the salt from this recipe.
- Watch your cookies closely while they bake or they may brown too quickly.
- Let your cookies cool completely before frosting or your filling will melt.
Nutrition
I am not a nutritionist or dietitian, any nutrition information provided is an estimate.
Did you make this recipe? Do you have questions? Let me know below!