Chewy chocolate chip cookies with a butterscotch flavor and packed with chocolate. These cookies are made with egg yolks & sourdough starter (fed or unfed) which gives the cookies an ultra chewy texture. The long rest deepens the flavor of the cookie dough.
While considering the development a recipe for sourdough chocolate chip cookies I had to ask – why? Would it be just a recipe to use up our ever growing jar of discard or would the starter itself add anything to the recipe that I couldn’t get from a non-sourdough chocolate chip cookie recipe?
What I discovered in my many sourdough cookie tests is that the flavor isn’t really what changes (though it’s there if your senses are wise to it) but the magic lies in the texture. Turns out, starter makes for a wonderfully chewy cookie!
But I didn’t want to stop there and sought a way to further enhance the caramel/butterscotch/toffee flavor you get from the maillard reaction as well. Let’s talk about it.
I knew that in adding starter to the dough (which is comprised of water and flour), I would need to omit some of the flour and some water from the dough. The ‘water’ portion would either need to come from the eggs or from browning the butter. While I love me a browned butter chocolate chip cookie, you must know by now that I am a massive fan of egg yolk chocolate chip cookies and am always ready to use yolks only.
For this recipe I went with just two yolks, and split the sugar (did you know sugar is a ‘wet’ ingredient?) and toyed around with how much starter to add (many recipes will do 100g discard, I quickly found this to be more than I needed) and with chill times: baked right away the cookies spread too much and had an airy texture. Chilled 24 hours without a cover on the dough they spread great but dried out quickly the next day. 24- 48 hours with a cover was the perfect answer. I also tried with fed and unfed and pretty much got the same result.
I also wanted to deepen the cookie’s flavor so I cooked the butter and sugar together, as I do in these butterscotch blondies, before adding it to the dough. It makes for an absolutely scrumptious butterscotch flavored cookie dough.
I have read in a few places that this rest period will ‘ferment’ the dough so it’s more digestible. I can’t speak to that but what I can tell you is that the rest will vastly improve the flavor, hydrate the flour, make it easier to scoop (it’s a rather sticky dough) and for our purposes here the chill will give the dough time to turn cohesive and cookie like; rather than a cookie with a bread-like texture.
Butter: unsalted butter. If using salted, halve the amount of salt added later.
Brown sugar: light or dark brown sugar. It should be soft.
Sugar: fine granulated sugar.
Egg Yolks: two whole egg yolks, reserve the whites for another use.
Sourdough Starter: fed or unfed works for these, so whatever you have. I generally prefer discard (unfed).
Vanilla: pure vanilla extract or vanilla bean paste.
Salt: fine sea salt. If using table salt, halve the amount.
Flour: all purpose flour, mine has a protein content of about 11%. If yours has less, the cookies will likely spread more.
Leavening: baking soda.
Chocolate: semi-sweet, dark chocolate or milk chocolate. Chopped chocolate chunks or use chocolate chips.
Set the butter and sugar in a pot over medium low heat.
Let the butter melt and stir with the sugar until combined. Cook, stirring often, until it begins to bubble.

Let it bubble for about a minute then take it off the heat. Pour the mixture into a large bowl and whisk very well.
Add the salt and vanilla and whisk to combine
Whisk in the egg yolks (reserve the whites for another use, maybe these double chocolate chip cookies). You’ll see the mixture turn thick and shiny as you whisk.
Add the sourdough starter discard to the mix and whisk to combine
Add the flour and leavening and stir

Chop up the chocolate into a mix of fine and large pieces (or use chocolate chips) and fold them in
Cover the bowl with plastic wrap to seal and set in the fridge. Chill for 24-48 hours (yes a full 24 but preferably 48!)
When it’s time to bake, take the cookie dough out of the fridge to soften a bit (so it’s easier to scoop)
Preheat the oven to 350 F and prep two cookie sheets with parchment paper
Use a disher or cookie scoop to portion the cookies into 2 tablespoons of dough per cookie, leaving a two inch border around the cookie dough balls.
Optional: sprinkle with flaky sea salt.
Bake the cookies for 12-15 minutes, until the edges are golden and the center does not look wet
The day of baking the edges will be crispy and the middles soft and chewy
Store leftover cookies in an airtight container, they will become chewy all around and will last up to 3 days.
The cookie dough needs to rest for a full day in the fridge before baking so it will need to be made at least a day ahead of time.
If you want to make it two days ahead of time, the cookie will be fine in the fridge for 48 hours (as long as it is sealed).
If you want to make the dough earlier and store it in the freezer, make the dough, do the 24 hour chill, portion the cookies onto a plate and freeze them for 15 minutes until solid. Then transfer them to a freezer-safe bag for longer storage.
Important: Before baking frozen cookie dough, allow it to come to room temperature on a parchment-lined baking sheet. Then bake as directed.

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absolutely divine. Just from rolling the dough in my hands I knew it would be a perfect cookie and all my friends gushed about the amazing texture. the sour dough doesn’t taste really tangy but gives it a less sugary, more-ish aroma, and a soft center while the edges caramelised perfectly.
Made this recipe today, couldn’t wait for 24 hour chill time so I baked it after 6 hour chilled and it still turns out AMAZING. Imo it’s not too sweet (which is a great dessert compliment in Asian household). Loved everything about this recipe, from the ingredients, execution, taste, texture. Hits every sweet spot. Thank you Sam for this recipe <3
I am excited but haven’t baked them yet… It would be helpful to add a rough cooling time so I could set a timer and do something other than check on it constantly. Excited for the recipe!
I just finished the dough it went well but idk if I over mixed because my chocolate chips were melting is this a bad sign?
Hi! After the cooking step I ask you to let the sugar/butter mixture cool. It sounds like it didn’t cool fully before you proceeded and so the chocolate started to melt. It’s not the worst thing, just means you’ll have streaks of chocolate through the dough rather than bits of chocolate.
These cookies were so good! What a great way to use sourdough discard! Yum!
Is it possible to add any nuts in this recipe?
I think that would be fine!
Smooth as silk. First chocolate chip cookies made with discard sourdough starter. Think I’m in love, seem so rich, with a burst of 60 % Ghirardelli Cacao. Looking forward to my first sourdough loaf. Little nervous, but oh so excited. Thanks for recipe.
Congrats on starting the sourdough journey! Hope the loaf turns out great (and if not it’ll still be tasty!) and I’m thrilled you loved the cookies 😀
One of the best chocolate chip cookies I’ve eaten. I only had bread flour on hand but the end result was that the cookies didn’t spread much. I gently flattened the second batch before popping oven. Perfectly chewy in center and crisp on the edges. Happy accident as someone once said. Thank you! Love your website.
Definitely see that happening with bread flour, glad you found a way to make them good!
I rarely leave reviews but I just had to let you know that all five of my kids deemed these “the best cookies ever.” Thank you!
oh gosh Mona, that’s wonderful to hear =) =D
I made this last week and have been DREAMING about it since then! The dough was so soft yet perfectly structured, it’s such a delicious recipe! Remaking tonight with my leftover sourdough discard!!
this is SO lovely to hear. Thank you =)
I made these today following the recipe exactly but using fresh ground whole wheat flour, because my starter is made of that. You are essentially making a caramel to start the dough with, and I love that idea! I just put the dough in the refrigerator and it tastes delicious. Can’t wait to bake them tomorrow night! Like others have said, thanks for your time and effort in making delicious recipes. I have made many of yours and have loved them, becoming my new favorites!
these are amazing! great way to use sourdough discard. might need to make these every week. mine didn’t spread too much even after dropping them — wondering if my dough was still too chilled when I started baking or because I rolled them into balls. I’ll try it a little different next time to see if I can get them flatter. either way though I was very happy with the flavor and texture. great recipe!
These were pretty good. I think I maybe over baked a bit for my preference but I’ll adjust next time. Curious what temp you cook the caramel to at the beginning of the recipe? Mine was paler than pictured here.
Hi Grace! The paleness is determined mostly by the sugar; in the photos I had used dark brown sugar.
These turned out ahhhmazing!! These recipes are always crowd faves and I appreciate all the background content!! Thank you for all the time you put into developing the recipes!
Kristin thank you, I’m thrilled to hear it!
I’ve “kind of” just finished the dough, for it’s stint in the fridge. Wished I’d read fully before preparing. You say when to add the baking powder, but there is none listed in the ingredients….I winged it and used 1 tsp. No mention in the recipe when to add the vanilla.
Hi Jeff, there’s no baking powder needed. I had it in an earlier test and forgot to remove it from the instructions. Salt and vanilla go in with the yolks. It’s all fixed now.