When one dives into the world of sourdough baking and bakes with any regularity, we will inevitably wind up with jars and jars of sourdough discard. I see a lot of recipes all across the internet for what to do with the leftover starter that does not make it into beautiful, aerated loaves. More often than not, the discarded results lean savory (I’m guilty of this myself!) So for this week, I wanted to try something different. Something sweet. And when you are like me and order peanut butter by the five-pound bucket, you make oatmeal peanut butter sourdough cookies.

Whew! That is a mouthful, I know. Oatmeal peanut butter sourdough discard cookies. Say it ten times fast. Then say it ten times fast with a mouthful of oatmeal peanut butter sourdough discard cookie. Heh, I kid. Or do I?
Peanut Butter Sourdough Cookies? Seriously?
In all seriousness, I am obsessed with these cookies. You can’t ever go wrong with classic oatmeal, but sometimes I just want something a little bit different. These were born out of a desire for oatmeal and frustration at having a full quart-sized jar of discard in my refrigerator that needed to be used up. There can only be so many recipes for sourdough discard pancakes, waffles, and pizza dough out there, right? Gimme something sweet! I love a well proportioned sweet and tangy combo in my baked goods- when it’s done well, it hits all the right spots on my tongue. If this is also you, then these cookies are definitely right up your alley.
Putting The Cookies Together:
These cookies are a particular favorite of mine because they come together with fewer than 10 totally plant-based ingredients:
- Peanut butter
- Brown sugar
- Coconut oil
- Flax eggs (ground flaxseed & water)
- Sourdough starter
- Rolled oats
- Baking Soda
- Baking Powder
- Kosher salt

The first thing you’ll want to do is make your flax eggs. In a small dish, mix together two tablespoons of ground flaxseed with six tablespoons of warm water. Still thoroughly and set aside.
Next, mix ALL remaining ingredients together in a large mixing bowl. It’s true! Another perk is that these are almost 100% a dump it all in a bowl and mix the ingredients until fully incorporated.
Once your dough is mixed chill for at least 30 minutes. This a key step because we are working with coconut oil. You want to make sure that the coconut oil stays firm when you’re rolling the dough into balls and putting it in the oven, or else the dough does melt and fall apart fairly quickly. Baker beware.

Bake the cookies for 15-18 minutes at 350 degrees, until the edges are slightly browned. If the dough is thoroughly chilled before baking, the cookies will still spread but not too much. If the dough is under-chilled, they will flatten like sad, crispy pancakes. Nobody wants a sad, crispy pancake.

Allow the cookies to cool for five minutes on the sheet pan before transferring to a cooling rack; they will be much less fragile after cooling.
Peanut Butter Oatmeal Sourdough Discard Cookies
Equipment
- Stand Mixer with paddle attachment
- Large baking sheet
- Silicone baking mat or parchment paper
- large mixing bowl
Ingredients
To Make The Flax Egg
- 2 tablespoons ground flaxseed
- 6 tablespoons water warm
To Make The Cookies
- 250 grams creamy peanut butter natural, no sugar added
- 275 grams brown sugar packed
- 225 grams coconut oil slightly softened, but not melted
- 200 grams rolled oats
- 150 grams sourdough starter discard, can come straight from the refrigerator
- ½ teaspoon kosher salt
- 1 teaspoon baking soda
- 1 teaspoon baking powder
Instructions
- Prepare the flax eggs. In a small bowl, whisk the ground flaxseeds and water together with a fork. Set aside.
- In a large mixing bowl, combine all the remain ingredients. This can be done either in a stand mixer fitted with a paddle attachment, or in a bowl with a spatula.Add the flax egg to the mixture last, and continue to mix until all ingredients are fully incorporated.
- Chill the dough for a MINIMUM of 30 minutes, but up to two hours.
- Preheat oven to 350°
- On a baking tray lined with parchment or a silicone baking mat, scoop generous 1-2 tablespoon-sized balls of dough.
- Bake for 15-18 minutes, or until the edges of the cookies become golden brown.
Try these cookies out and let me know in the comments how you liked them! Or give them a shot and tag me on Pinterest or Instagram @kettleandkale. I’ve started getting tagged in your creations and it’s so much fun to see!

SOOOOOOOOOOO YUUUUUUMMMMMYYYYYYYYYYYY!!!!!!!!!!!!!!!!!!
Mine came out totally flat! Any idea why? The only thing I can think of is that I did melt the coconut melt a bit. ><
I have definitely had this issue when the coconut oil isn’t hard and firm! It’s a bit of a finicky ingredient in this regard, but I would try again, making sure that the coconut oil is nice and firm 🙂
Followed recipe to the “tee”, made sure coconut oil was still somewhat solid. Came out totally flattened, but dough tasted do good. sure seems line *alot* of oil to me. My other vegan cookie recipes do not call for that much oil and then you’ve got the oil from the peanut butter . And no flour ? Seems to me it needs added flour. Was so excited to make these. Maybe I’ll use as a crust for chocolate pie.