Sourdough S’mores Skillet Cookie to Share

There are two things I truly love in life: sourdough and campfires. And since moving to British Columbia, I’ve discovered a whole new passion for s’mores. With this shareable skillet cookie, it’s literally two of my favourite worlds coming together in one cast iron pan. Picture this: a thick sourdough cookie dough, pieces of graham crackers, chocolate melting gently, and big soft marshmallows tucked between two layers of dough. It’s the kind of dessert you serve family style: set it in the middle of the table, and everyone helps themselves to their own little portion. It would be delicious with a small scoop of ice cream.
And the best part? Your sourdough discard (or active starter, both work) finally gets a new life. Flora approves. ✨

Why this recipe

S’mores are wonderful when you’re camping, but we don’t always have a campfire within reach. This recipe brings back all the magic of s’mores — that graham cracker taste, the melty chocolate, the golden marshmallow — without leaving the house. The sourdough adds a lovely depth of flavour, a subtle hint of tang that balances the sweetness. The result is a big cookie with golden edges, tender and gooey in the centre, with soft little pockets of marshmallow in every bite.
It’s also a lovely recipe for entertaining: simple to make, comforting, and always a crowd favourite.

The role of each ingredient

The sourdough starter: it adds moisture, a softer texture and that little touch of complexity that makes people ask, “what’s your secret?”. You can use unfed discard or an active starter — it doesn’t need to be at its peak.

The butter: creamed with the sugars, it gives a rich dough and edges that caramelize gently in the cast iron.

The brown sugar: it leads here, for a caramel flavour and a nice tender centre. The white sugar balances things out and helps the edges turn golden.

The baking soda: it gives the dough a gentle lift and helps with that lovely golden colour. With the acidity of the sourdough, it works even better.

The graham crackers: folded into the dough and layered on top, they bring that signature s’mores crunch.

The marshmallows: cut in half and hidden in the middle, they melt into soft, pillowy pockets. The ones on top turn golden in the oven, a little like over a fire.

The chocolate: semi-sweet chips in the dough, plus milk chocolate pieces for that true classic s’mores taste.

Why it’s so good

One skillet, no cookie dough balls to shape, no baking sheets to keep an eye on. You layer the dough, add the toppings, and pop it in the oven. It’s the perfect dessert when guests show up at the last minute or when the kids are craving a little something special on a Friday night. Served warm with ice cream slowly melting on top, it’s a truly lovely little moment of happiness.

My tips

• Use a well-buttered 10-inch cast iron skillet. Cast iron holds the heat beautifully and gives you gorgeous golden edges.
• Keep an eye on the baking: the centre should still be slightly gooey when you take the skillet out of the oven. It will keep cooking gently as it cools.
• Save a few graham cracker pieces and marshmallows for the top: that’s what gives it that beautiful s’mores look.
• If the top is browning too quickly, you can loosely cover it with aluminum foil for the last few minutes.
• Let it rest for about ten minutes before serving: the marshmallow is very hot straight out of the oven, and the cookie holds together better after a short rest.
• No cast iron skillet? A 9 or 10-inch round oven-safe pan works just fine.

Storage

The cookie keeps at room temperature, well covered, for up to 3 days. To bring back that gooey centre, warm a portion in the microwave for about fifteen seconds, or return the skillet to a 300 F oven for a few minutes. You can also freeze well-wrapped individual portions for up to 2 months.