Peanut Butter Oatmeal Sandwich Cookies With Sourdough Discard


Last Updated: Apr, 3, 2026 by Mimi Council | This post may contain affiliate links.

These Peanut Butter Oatmeal Sandwich Cookies With Sourdough Discard are a take on the iconic Do Si Dos, which are classic Girl Scout cookies! Crispy peanut butter oatmeal cookies are filled with creamy peanut butter frosting. You’ll want a glass of milk for dipping these classics!

If you’re looking for more nostalgic cookies, be sure to check out some of my other favorites like Organic Thin Mint Cookies, Chocolate Covered Peanut Butter Cookies (Homemade Tagalongs), Homemade Peanut Butter Oreos, or Homemade Vanilla Oreo Cookies.

peanut butter oatmeal sandwich cookies on a white ruffle plate on marble counter.

A Quick Look At The Recipe

  • Recipe Name: Peanut Butter Oatmeal Sandwich Cookies With Sourdough Discard
  • Ready In: 4 hours 35 minutes
  • Makes: 22 sandwich cookies
  • Main Ingredients: salted butter, peanut butter, light brown sugar, powdered sugar
  • Flavor Profile: tangy sourdough peanut butter sandwich cookies with a sweet peanut butter filling
  • Dietary Info: eggless, no seed oils
  • Difficulty: Medium
  • Why You’ll Love It: better than the Do Si Dos girl scout cookies!

Why You’ll Love This Recipe

  • Better Than the Box: These organic cookies are a homemade version of the orange box Girl Scout cookies! Free of seed oils, soy, and flavorings, these peanut butter cookies are a mindful choice instead. Just like Eggless Cosmic Brownie Cookies and Soft Sugar Cookies With Pink Frosting, these are a nostalgic treat made better at home!
  • Uses Sourdough Discard: I use sourdough discard in these sandwich cookies which uses up waste and gives these peanut butter oatmeal sandwich cookies an original flavor that’s oddly nostalgic! If you make sourdough bread often, this is a great discard recipe for you sourdough bakers.  Also try Vegan Sourdough Chocolate Chip Cookies that uses up sourdough discard for delicious cookies!
  • Rich Peanut Butter Flavor: If you’re a peanut butter lover, then you’ll be obsessed with these sourdough peanut butter cookies.
  • Sandwich Cookies: I love sandwich cookies as they’re two cookies in one — the ultimate indulgence just like Soft Baked Pumpkin Spice Cranberry Sandwich Cookies, Earl Grey Sandwich Cookies, and Soft Baked Snickerdoodle Sandwich Cookies.
  • Eggless Cookies: No eggs needed for these do-si-dos, as sourdough discard is a great egg replacer. I love making sourdough discard recipes if you don't have eggs!
Jump to:

What are Do Si Dos?

Do Si Dos are one of the iconic Girl Scout cookies that has been around since the 1950s. This flavor used to be called the peanut butter sandwich, which basically describes it perfectly. The name was later changed to Do Si Dos (not sure why). These Girl Scout Cookies are crispy peanut butter oatmeal sandwich cookies with creamy peanut butter filling.

If you’re a fan of Girl Scout cookies, but not harmful ingredients then you’ll love these Peanut Butter Oatmeal Sandwich Cookies with Sourdough Discard! These homemade sandwich cookies have the buttery richness of these peanut butter shortbread cookies but with only 9 organic ingredients. These nutty cookies are also free of seed oils, soy, and flavoring that you will find in traditional Do Si Dos!

This is another collab with my friend Hannah at Make It Dough! Check out some of our other cookie collaborations like Sourdough Jam Thumbprint Cookies, Sourdough Chocolate Shortbread Cookies, Cranberry Orange Biscotti with Sourdough Discard, or Eggless Sourdough Molasses Cookies.

Ingredients

individual ingredients for peanut butter oatmeal sandwich cookies with sourdough discard laid out against a white background.
  • Brown Sugar: I use homemade light brown sugar for added rich flavor in these organic cookies.
  • Vanilla Extract: Make sure to use a high quality vanilla extract, not imitation.
  • Peanut Butter: I use organic creamy peanut butter, my favorite is Costco! This is natural peanut butter, which you have to stir because it only has 2 ingredients.
  • Sourdough Discard: You can use your sourdough discard straight from the fridge, you don't have to have active sourdough starter.  If you don’t have sourdough discard, you can replace it by mixing together 21 grams all purpose flour and 21 grams of water, use that’s in its place. It won’t have the same tangy flavor, but the cookies will still be delicious!
  • Milk: I use organic whole milk for the most creamy frosting.
  • Oats: I use organic rolled oats, which are also the same as old-fashioned oats.

*For a full list of ingredients and measurements, visit the recipe card below.

Baker’s Tips for Peanut Butter Oatmeal Sandwich Cookies With Sourdough Discard

  • Always weigh ingredients for the best results.
  • Make sure your butter is softened for both the cookie dough and the filling. It's best to leave it at room temperature to soften naturally.
  • I use a stand mixer, but if you want to use a hand mixer, you can also do that. 
  • Use a creamy peanut butter, not chunky. And, use a high quality organic peanut butter, skip the standard Jif or Skippy as those will not give you the best flavor as they have unnecessary ingredients like seed oils and more.
  • If you don’t have sourdough discard, you can mix together 21 grams all purpose flour and 21 grams water in a small bowl and use that’s in its place.

How to Make Peanut Butter Oatmeal Sandwich Cookies With Sourdough Discard

butter and brown sugar in a stand mixing bowl on a white marble counter.
  1. To make the dough: In the bowl of a stand mixer fitted with the paddle attachment, add the butter, brown sugar, and vanilla extract.
peanut butter oatmeal cookie dough in a stand mixing bowl on a marble counter.
  1. Mix on low until combined and there are no butter chunks.
ingredients for peanut butter oatmeal cookies in a stand mixing bowl on a marble counter.
  1. Add in the sourdough discard and peanut butter.
ingredients for peanut butter oatmeal cookies in a stand mixing bowl on a marble counter.
  1. Next, add flour, and oats.
peanut butter oatmeal cookie dough in a glass mixing bowl on a marble counter.
  1. Mix to combine into a stiff cookie dough.
peanut butter oatmeal cookie dough rolled into a log and wrapped in plastic wrap on a white marble counter.
  1. 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.
peanut butter oatmeal cookie dough sliced into slices on a wood cutting board.
  1. 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.
peanut butter oatmeal cookie dough slices on a baking sheet on a white marble counter.
  1. Place on the prepared baking sheets. Poke the tops of the cookies with a fork a couple of times.
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.
peanut butter frosting in a glass mixing bowl on a white marble counter.
  1. To make the filling: In the bowl of a stand mixer fitted with the paddle attachment, add the butter, powdered sugar, peanut butter, vanilla, 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.
peanut butter oatmeal cookies with peanut butter filling on a baking sheet.
  1. 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.
peanut butter oatmeal sandwich cookies in a baking sheet on a marble counter.

Recipe FAQ’s

What are Do Si Dos cookies?

Do-Si-Dos are a classic peanut butter sandwich Girl Scout cookie with a crispy, buttery peanut butter cookie and creamy peanut butter filling.

What makes Do-Si-Dos different from regular peanut butter cookies?

Classic peanut butter cookies are typically soft and chewy. Do Si Dos are a crunchy peanut butter sandwich cookie filled with a creamy peanut butter filling.

What is sourdough discard?

Sourdough discard is the excess sourdough starter that is removed during the feeding process. Instead of throwing it out, you can use it in other baked goods to infuse a tangy sourdough flavor!

Can I use crunchy peanut butter instead of smooth?

No, you should use creamy peanut butter as it will give the cookies a better texture and allow you to easily slice them without them breaking because of little pieces of nuts.

What kind of peanut butter is best for Do Si Dos?

I use organic creamy peanut butter, which is what I recommend. Look for peanut butter with only 2 ingredients: peanuts and salt.

Can I use natural peanut butter?

Yes! This is what I use here, organic creamy peanut butter with just peanuts and salt.

Can I make these cookies gluten-free?

No, because we're using sourdough discard in these cookies, I don't have a gluten free swap here.

Why are my peanut butter cookies dry or crumbly?

This is probably because the ingredients were measured incorrectly. Be sure to weigh ingredients for the best results.

How do you store peanut butter sandwich cookies?

Because these sandwich cookies are crispy, they are best stored in a cool, dry place.

Can I freeze the dough or the baked cookies?

Yes, you can freeze both if you would like. For the dough, just freeze the wrapped dough log. Then thaw it in the fridge for 24 hours before slicing and continuing with the recipe. If you are freezing baked cookies, just store in an airtight container in the freezer for up to 3 months.

peanut butter oatmeal sandwich cookies with sourdough discard on a baking sheet on the oven.
peanut butter oatmeal sandwich cookies stacked on a white marble counter with a glass of milk.

More Peanut Butter Desserts

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peanut butter oatmeal sandwich cookies on a white ruffle plate on marble counter.

Peanut Butter Oatmeal Sandwich Cookies With Sourdough Discard

Mimi Council
Indulge in homemade Do Si Dos, the iconic Girl Scout cookies filled with creamy peanut butter frosting and oatmeal goodness. These Peanut Butter Oatmeal Sandwich Cookies With Sourdough Discard are even better than the ones in the box! Plus, this cookie recipe uses up sourdough discard for a slight tang that is so good with the peanut butter flavor.
5 from 1 vote
Prep Time 15 minutes
Cook Time 20 minutes
Chill time 4 hours
Total Time 4 hours 35 minutes
Course Dessert
Cuisine American
Makes 22 sandwich cookies
Calories 253 kcal

Equipment

  • Digital Food Scale
  • Stand Mixer
  • Half Sheet Pan
  • Parchment Paper
  • Piping Bag

Ingredients
 
 

Dough

  • 226 grams salted butter (softened)
  • 113 grams light brown sugar
  • 2 teaspoons vanilla extract
  • 43 grams sourdough discard
  • 57 grams peanut butter
  • 255 grams all purpose flour
  • 50 grams rolled oats

Filling

  • 113 grams salted butter (softened)
  • 226 grams powdered sugar (sifted)
  • 57 grams peanut butter
  • ½ teaspoon vanilla extract
  • 1 to 2 tablespoons milk

Instructions
 

  • To 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.
  • Add in the sourdough discard, peanut butter, flour, and oats and mix to combine into a stiff cookie 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.
  • 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 of times.
  • Bake for 20 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.
  • To make the filling: In the bowl of a stand mixer fitted with the paddle attachment, add the butter, powdered sugar, peanut butter, vanilla, 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.
  • 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.

Video

YouTube video

Notes

Tips
  • Always weigh ingredients for the best results.
  • Make sure your butter is softened for both the cookie dough and the filling. It's best to leave it at room temperature to soften naturally.
  • I use a stand mixer, but if you want to use a hand mixer, you can also do that.
  • Use a creamy peanut butter, not chunky. And, use a high quality organic peanut butter, skip the standard Jif or Skippy as those will not give you the best flavor as they have unnecessary ingredients like seed oils and more.
  • If you don’t have sourdough discard, you can mix together 21 grams all purpose flour and 21 grams water in a small bowl and use that’s in its place.
  • High Altitude — Follow the recipe as noted.

Nutrition

Calories: 253kcalCarbohydrates: 27gProtein: 3gFat: 15gSaturated Fat: 9gPolyunsaturated Fat: 1gMonounsaturated Fat: 5gTrans Fat: 1gCholesterol: 33mgSodium: 124mgPotassium: 62mgFiber: 1gSugar: 16gVitamin A: 386IUCalcium: 14mgIron: 1mg
Want more recipes?Follow along on @mimisorganiceats for more inspiration!

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One response to “Peanut Butter Oatmeal Sandwich Cookies With Sourdough Discard”

  1. Mimi Council says:

    5 stars
    So much better than Girl Scouts!

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