These sourdough s’mores cookies are soft, chewy, and packed with gooey marshmallows, Hershey's chocolate pieces, and crunchy sourdough graham cracker pieces. Made with sourdough discard, they’re a fun and delicious way to add a tangy twist to a nostalgic campfire treat.

6 sourdough s'mores cookies sitting on a round black serving board. There are some decorative items surrounding the board, but these are ingredients that have been used in the sourdough s'mores cookies.

If you love making sourdough cookies, you might also like to try these sourdough snickerdoodles, sourdough gingerbread cookies or these sourdough chocolate chip cookie bars.

Why You'll Love This Recipe!

Like S'mores Only Better - I've combined everything you love about sourdough chocolate chip cookies with all the best things about s'mores! It's a win win!

Nostalgic Campfire Flavor – With gooey marshmallows, melty chocolate, and graham cracker crumbs, these cookies capture all the cozy, toasty flavors of classic s’mores in one bite, but with a delicious sourdough twist.

No Campfire Required – You get all the fun and flavor of s’mores without needing a fire—just bake and enjoy straight from your kitchen. They also make a wonderful addition to cookie platters and gift boxes.

A stack of 5 sourdough s'mores cookies photographed close up. You can also see a piece of Hershey's Milk chocolate sitting in front of the stack.

Ingredients

All Purpose Flour
Corn Starch - I add this ingredient to most of my cookies. It stops them spreading too much and also keeps the centres soft and chewy.
Baking Soda
Salt - I've added a little to the dough to balance the flavors and sprinkled some flaky sea salt on top for a savory finish (this is optional).
Chocolate Chips - I've used a mix of half milk chocolate and half semi sweet chocolate chips.
Sourdough Starter - you can use either sourdough starter or sourdough discard for this recipe.
Butter - I've used salted, melted butter.
Sugar - I've used a blend of white granulated sugar and brown sugar to create soft cookies with crispy edges, perfect for topping with chocolate pieces and marshmallows.
Eggs - a large egg as well as an egg yolk is necessary to make these delicious cookies.
Vanilla Extract - you can use vanilla extract or vanilla paste.
Marshmallows - I've used white marshmallows, cut in half. You could also use mini marshmallows. I don't recommend using anything too big or they can make a big mess and detract from the other elements of the cookies.
Graham Crackers - you can use any graham crackers you like, I've used Sourdough Graham Crackers for a truly authentic sourdough flavor.
Hershey's Chocolate Pieces - 3 Hershey's bars broken into pieces is plenty to create the right milk chocolate flavor for these cookies. I haven't used Hershey's in the cookies themselves, only on the top of the cookies.

How to Make Sourdough S'mores Cookies

This recipe for sourdough s'mores cookies uses my tried and tested sourdough chocolate chip cookie recipe. I recommend reading through that post too as it contains lots of tips for success when making these cookies.

Making the Cookie Dough

Place some of the dry ingredients (flour, baking soda, corn starch, salt and chocolate chips) into a large mixing bowl and combine. Set this aside.

Now in a separate bowl, combine sourdough starter, melted butter, brown sugar, white sugar, egg + egg yolk and vanilla extract. Stir together until they resemble runny caramel.

Now pour the wet ingredients into the dry ingredients and stir to form the cookie dough.

Cover the bowl with plastic wrap and place into the fridge for 12 to 24 hours.

Baking the Cookies

The next day, when you are ready to bake the cookies, preheat the oven to 165C (330F) and line two cookie sheet with parchment paper.

Use a cookie scoop or large spoon to scoop out balls of dough. I have used 65g dough balls for this recipe. Larger balls are better as it provides more surface area for the s'mores toppings to go on.

Place the dough balls onto the prepared baking sheets.

A photo taken overhead showing the process of making the cookie dough balls. You can see 5 cookie dough balls sitting on a cookie tray. Around the tray is the bowl of sourdough chocolate chip cookie dough, as well as the s'mores toppings including marshmallows, Hershey's pieces, graham cracker crumbs and a small bowl of flaky sea salt.

Place the cookies into the oven for 10 minutes at 165C (330F). The cookies won't be fully baked at this point, but this is when you'll add the s'mores toppings.

Adding the Toppings

Carefully remove the par baked cookies from the oven and add some of the toppings to each cookie. I like to smoosh the cookie gently with a spoon first and then press in a few broken pieces of Hershey's chocolate, a few marshmallow halves and sprinkle over some graham cracker crumbs and a little flakey sea salt. You can add as much or as little toppings as you like. Try to smoosh the toppings in a little to ensure they bake into the cookies.

A close up photo of the par baked s'mores cookies after the toppings have been added and before they are about to go back into the oven to melt the marshmallows.

Return the sourdough s'mores cookies to the oven to bake for around 5 to 8 minutes, depending on the texture you prefer. Keep an eye on them as the marshmallows can melt off the cookies if you leave them too long.

Once you're happy and the edges of the cookies are golden, remove from the oven and allow to cool on the tray for around 10 minutes. The cookies will continue to bake for a few minutes after they are removed from the oven and will firm up as they cool.

After 10 minutes, carefully transfer to a wire rack and allow them to cool completely.

5 sourdough s'mores cookies that have just been pulled out of the oven. The cookies are sitting on a baking sheet that is a top a large wooden board.

Kate's Recipe Tips

These cookies are really soft when you first remove them from the oven, so make sure you allow them to cool on the tray first before you try to put them on a cooling rack. Removing them too soon will cause the cookies to break.
Smooshing the toppings into the par baked cookies will ensure everything sticks. Add some of the graham cracker crumbs on top of the marshmallows to ensure everything stays on top of the cookies.

How To Store + Freeze

You can store these cookies in an airtight container for up to 7 days. I recommend using a metal cookie tin or a glass jar for the best results, although if you don't mind a softer texture, plastic containers can be fine too. I like to line my plastic containers with some paper towel to absorb some of the moisture.

You can freeze the un baked cookie dough balls in zip loc bags. I don't recommend freezing the baked cookies as the texture of the marshmallow can become brittle.