Copycat Costco Viral S’mores Cookie Recipe – Gooey, Chewy, and Loaded With Marshmallow

These s’mores cookies blew up for a reason: they’re soft, gooey, and stacked with chocolate and marshmallow in every bite. If your Costco is sold out or you don’t have a membership, you can still get that same craveable cookie at home. This recipe nails the thick, bakery-style texture with toasty edges and a molten center.

It’s simple, uses pantry staples, and bakes up beautifully every time. Get ready for warm, melty cookies that taste like campfire s’mores without the mess.

Why This Recipe Works

• Chilled dough for structure: A short chill helps the cookies bake thick and prevents excessive spread.
• Two chocolates: Chips for classic pockets and chopped bar chocolate for melty pools, just like the viral version.
• Mini marshmallows inside and on top: Some mix in, some finish on top for that gooey, toasty look.
• Graham cracker crumbs in the dough: They add flavor, texture, and a touch of nostalgic crunch.
• Big cookie size: Large scoops mimic that bakery feel—crispy edges, soft center.

What You’ll Need

• 1 cup (226 g) unsalted butter, cold and cubed or softened
• 1 cup (200 g) light brown sugar, packed
• 1/2 cup (100 g) granulated sugar
• 2 large eggs, room temperature
• 2 teaspoons vanilla extract
• 2 3/4 cups (345 g) all-purpose flour
• 1/2 cup (55 g) finely crushed graham cracker crumbs (about 5–6 full sheets)
• 1 teaspoon baking soda
• 1/2 teaspoon baking powder
• 3/4 teaspoon kosher salt (use 1/2 teaspoon if using table salt)
• 1 cup (170 g) semisweet chocolate chips
• 4 oz (115 g) chopped milk chocolate bar (or more semisweet if you prefer)
• 1 1/2 cups mini marshmallows, divided
• 3–4 full graham cracker sheets, roughly broken for topping
• Optional: flaky sea salt, for finishing

How to Make It

1. Prep the pans: Line two baking sheets with parchment paper. Set oven rack to middle position.
2. Beat the butter and sugars: In a large bowl, beat butter, brown sugar, and granulated sugar on medium-high for 2–3 minutes until light and creamy. Scrape the bowl.
3. Add eggs and vanilla: Mix in eggs one at a time, then add vanilla. Beat until smooth and slightly thickened.
4. Combine dry ingredients: In a separate bowl, whisk flour, graham crumbs, baking soda, baking powder, and salt.
5. Bring it together: Add dry ingredients to the wet and mix on low just until no dry streaks remain. Do not overmix.
6. Fold in the goodies: Stir in chocolate chips, chopped chocolate, and 1 cup of the mini marshmallows. Reserve the remaining 1/2 cup for topping.
7. Portion big scoops: Use a large cookie scoop (about 3 tablespoons or 60–70 g each). Roll into balls and place on a tray.
8. Chill: Refrigerate the dough balls for 30–45 minutes. This helps keep them thick and chewy.
9. Preheat: Heat the oven to 350°F (175°C).
10. Top for s’mores effect: Press a few mini marshmallows and a small piece of graham cracker onto the top of each dough ball. Don’t overdo the marshmallows or they’ll melt off.
11. Bake: Arrange 6–8 cookies per sheet with plenty of space. Bake for 10–13 minutes until edges are set and lightly golden, but centers look slightly underbaked.
12. Circle for perfectly round cookies (optional): Use a large round cutter or bowl to gently scoot the hot cookies into neat circles.
13. Finish: While warm, sprinkle with flaky salt and press on a few extra chocolate chunks if you like picture-perfect pools.
14. Cool: Let cookies rest on the sheet for 8–10 minutes, then transfer to a rack. They’ll set as they cool but stay soft inside.

How to Store

• Room temperature: Keep in an airtight container for 3–4 days.Add a slice of bread to the container to maintain softness.
• Freezer (baked): Freeze cooled cookies in a zip-top bag for up to 2 months. Thaw at room temp or warm in a 300°F (150°C) oven for 5–6 minutes.
• Freezer (dough): Freeze scooped dough balls on a sheet tray until solid, then store in a bag for up to 3 months. Bake from frozen at 350°F (175°C) for 12–15 minutes.

Health Benefits

• Portion control: These are rich cookies, so one can satisfy a sweet tooth without overdoing it.
• Homemade advantage: You control ingredients—choose high-quality chocolate, reduce sugar slightly, or use dark chocolate for less sweetness.
• Mindful swaps: Sub some all-purpose flour with whole wheat pastry flour for a bit more fiber and a subtle nutty flavor.
• Allergy awareness: Making them at home helps you avoid unwanted additives and tailor to dietary needs.

Pitfalls to Watch Out For

• Overmixing the dough: It can make cookies tough. Mix just until combined.
• Too many marshmallows on top: They can melt and ooze off the cookie. Press on just a few.
• Skipping the chill: Warm dough spreads too much and loses that bakery thickness.
• Overbaking: Pull them when the centers look slightly underdone; they’ll set as they cool.
• Incorrect flour measurement: Spoon and level flour to avoid dry, cakey cookies.

Recipe Variations

• Dark chocolate + sea salt: Use all dark chocolate and finish with flaky salt for a richer, less sweet cookie.
• Peanut butter s’mores: Swirl 1/3 cup peanut butter into the dough or add peanut butter chips.
• Stuffed center: Wrap dough around half a large marshmallow or a square of chocolate for a molten core.
• Gluten-free: Use a 1:1 gluten-free baking flour and certified gluten-free graham crackers. Chill well to help with structure.
• Air fryer mini cookies: Scoop smaller portions and air fry at 325°F (165°C) for 6–8 minutes, checking early.
• Cinnamon touch: Add 1/2 teaspoon ground cinnamon to the dry mix for a cozy flavor twist.

FAQ

Can I use regular marshmallows instead of mini?

Yes, cut regular marshmallows into quarters with kitchen scissors.

Toss them lightly in cornstarch to reduce sticking, and use fewer pieces per cookie to prevent overflow.

Do I have to chill the dough?

Chilling is strongly recommended. It helps control spread, makes the cookies taller, and improves flavor as the flour hydrates.

Why did my marshmallows melt into puddles?

Too many marshmallows on top or placing them too close to the edges can cause runoff. Press a few into the center and bake on parchment, not a greased sheet.

Can I reduce the sugar?

You can cut up to 2–3 tablespoons from the granulated sugar without major texture changes.

Reducing more may affect spread and softness.

What chocolate works best?

A mix of semisweet chips for structure and chopped milk or dark chocolate for pools gives the best texture and flavor, similar to the viral version.

How do I make them extra thick?

Scoop larger (75–85 g), chill at least 1 hour, and bake on a cool sheet. If needed, chill dough balls between batches so they don’t warm up.

Can I make the dough ahead?

Yes. Keep covered in the fridge for up to 48 hours, or portion and freeze for longer storage.

Let chilled dough sit 10–15 minutes before scooping if too firm.

Final Thoughts

These copycat Costco s’mores cookies are everything you love about campfire treats in an easy, bakery-style cookie. They’re thick, melty, and loaded with chocolate and marshmallow, with just the right graham cracker crunch. Bake a batch for a party, a movie night, or just because.

Once you try them warm from the oven, you’ll see why they went viral—and you won’t miss the store-bought version one bit.