How to Make Costco Marshmallow Crispy Cookies at Home

People everywhere are going crazy over these new Costco Marshmallow Crispy Cookies, and let me tell you why! This new bakery item is soft, chewy, packed with pockets of melty marshmallow, and balanced perfectly with a light crunch from the crispy rice cereal. This cookie is honestly the best with this iced brown sugar coffee!

By browning the butter and adding a touch of corn syrup, you get a cookie that’s full of flavor, extra chewy, and slightly caramel-y. If you’ve ever grabbed a cookie from Costco and thought, “I wish I could make this at home,” you can now! Or if you don’t have a Costco membership but have been wanting to try these new cookies, here’s your chance.

Do these taste exactly like the Costco cookies?

In my humble opinion, they taste better than the Costco cookies, but keep in mind that industrially baked goods always have a slightly different mouthfeel and taste because they aren’t made with the same ingredients you and I have at home.

This Costco recipe, for example, uses mainly shortening with a butter flavoring to make them look, taste, and feel the way they do. In this copycat recipe, we used mainly butter that we browned to get that nutty flavor with a little shortening to keep it moist and chewy, since not everyone has brown butter flavoring on hand. If you love that browned butter flavor, you’ll also want to bake a batch of these brown butter scoopable chocolate chip cookies, which use the same nutty browned butter base.

So keep all of this information in mind when making these! You can look at the image above to see all the ingredients used in the cookie itself from Costco and compare them to what we are using in this recipe. If you are feeling adventurous, you can play around with ratios or add new things I may not have included from the ingredients above. Just know you might get a completely different result. You can also adjust ratios or add new ingredients I may not have included.

Homemade Costco marshmallow crispy cookies Ingredients

Here are the ingredients you will need to make these new marshmallow crispy cookies from Costco. Scroll down to the recipe card at the bottom of the page for the detailed ingredient measurements. 

• Unsalted Butter: browns slightly to deepen the cookie’s flavor.
• Shortening: adds extra chewiness and helps cookies hold their shape without spreading too much.
• Dark Brown Sugar: gives moisture and a subtle caramel flavor.
• Granulated Sugar: adds sweetness and slight crispness.
• Egg + Egg Yolk: helps bind all the ingredients together.
• Vanilla Extract: enhances the flavor.
• All-purpose Flour: provides structure for the cookie dough.
• Cornstarch: is optional but adds extra softness.
• Baking Powder and Soda: leavens and aerates the cookies.
• Kosher Salt: balances sweetness and enhances all the flavors.
• Light Corn Syrup: adds chewiness.
• Mini Marshmallows: gives soft pockets of sweetness and chewy texture throughout.
• Rice Krispies Cereal: added to the dough makes this delicious treat taste like a Rice Krispies Treat cookie.

How to make copycat Costco marshmallow crispy cookies at home

Here is how to make a copycat version of the Kirkland Signature marshmallow crispy cookies. Scroll down to the recipe card at the end of this post for full step-by-step instructions! If you’d rather skip the oven entirely, try my Crumbl Rice Krispies bar cookies, a marshmallow-and-cereal treat that comes together in minutes with no baking. My Ruffles Krispy treats swap in ridged potato chips for a sweet-and-salty spin on the same idea.

1. Melt your butter in a light-colored saucepan over medium heat. Stir constantly. Watch for it to foam, then develop golden-brown bits at the bottom. Pour it into a heatproof bowl, scraping in all those flavorful browned bits, and let it cool until slightly thickened.
2. In a mixing bowl, beat together the browned butter, shortening, dark brown sugar, and granulated sugar until light and fluffy.
3. Mix in the corn syrup, egg, egg yolk, and vanilla until smooth and fully combined.

4. In a separate bowl, whisk together the flour, cornstarch, baking soda, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients and mix until just combined, without overworking the dough.
5. Gently fold in the Rice Krispies and some of the mini marshmallows. Chill the marshmallows so they don’t melt into goo too early.
6. Cover the brown butter dough and refrigerate for 1 hour. This step helps the cookies hold their shape, keeps the marshmallows from oozing too much, and prevents excessive spreading.

7. Preheat your oven and line a cookie sheet with parchment. Scoop out roughly 3-tablespoon portions and leave plenty of space between them. Bake in the preheated oven until the edges are golden, but the centers are still slightly underbaked.

8. As soon as the cookies come out of the oven, use a larger cookie cutter than the cookies to swirl them around (see the photos below) so they are a perfect circle and keep any marshmallow that oozed out inside.
9. Working quickly, take a few mini marshmallows, break them in half, and stick them on the hot cookies to give them that signature Costco cookie look.
10. Let the cookies sit on the baking sheet before moving them to a wire rack. The marshmallows will firm up as they cool, giving you that perfect chewy-and-crispy combo.

Why make these Krispy marshmallow cookies?

• This recipe is perfect for people who aren’t Costco customers or don’t have a local store nearby.
• If you’re already a fan of the cookies but don’t want a huge 24-count container or want smaller cookies, this recipe is for you.
• The texture is absolute perfection, with soft, gooey marshmallow and crispy cereal combined into an ultra-chewy cookie.
• These unique cookies are a great choice for parties, baked goods sales, or an indulgent snack at home.
• They don’t use the usual preservatives that you find at industrial bakeries. For another easy Crumbl-inspired treat to add to your rotation, try these caramel apple Crumbl cookies, the same copycat-bakery magic with a fall twist.

Frequently asked questions – FAQ

Can I make smaller cookies instead of the giant Costco size?

Absolutely! Just keep in mind that smaller cookies bake a little faster, so watch them closely and pull them out when the edge is golden but the center is still soft.

Can I make the dough ahead and freeze it?

Yes! You can do so by scooping the dough into balls, freezing them on a baking sheet, then transferring them to a freezer bag once they’re frozen solid. You can bake them straight from frozen by just adding 1–2 extra minutes to the baking time.

Can I substitute the Rice Krispies cereal?

You can, but Rice Krispies are ideal for the light, crispy texture that balances the chewy marshmallows. Other cereals may change the texture or flavor. If you want to riff on the mix-ins instead, these peanut butter cornflake cookies swap in cornflakes and peanut butter for a different crunchy-chewy combo, and this strawberry Rice Krispy treats recipe uses freeze-dried strawberries for a fruity twist.

How should I store these copycat Costco marshmallow crispy cookies?

Store your leftover cookies in an airtight container at room temperature for 3 days or in the fridge for 5 days. My favorite secret to keep cookies extra soft is to add a piece of toast or tortilla to an airtight container with them; perfectly chewy cookies every time! These Nestle Toll House cookie bars store the same way, so it’s an easy trick to remember for both.

Can I make a gluten-free version of this recipe?

I haven’t personally tried it, but I’m sure you can as long as you swap the all-purpose flour for a 1:1 gluten-free flour blend. You may need to slightly adjust the baking time depending on your blend.