Brown Butter Marshmallow Rice Krispie Cookies

These cookies taste just like a rice krispy treat baked right into a cookie. The browned butter gives every bite a deep, nutty flavor, while the cereal adds crunch and the marshmallows melt into pockets of gooey sweetness.

What Makes This One Special

This one is my copycat take on the viral Costco cookies that have been all over TikTok, the giant bakery cookies loaded with rice krispies and marshmallows that people have been driving out of their way for. I almost bought them to try but I didn’t know what I would do with two dozen cookies. I couldn’t stop thinking about them, so instead I decided to recreate the concept at home, but with a browned butter base to give it even more depth of flavor than the original.

Browning the butter is really what sets this version apart. It adds this deep, nutty, almost caramel-like flavor that plays so well against the sweetness of the marshmallows and the crunch of the cereal. Every bite has that classic rice krispy treat flavor, but in cookie form, with crispy edges and a soft, chewy center. Let’s get into it.

How To Make It

Freeze the Marshmallows First

Before you do anything else, spread your mini marshmallows out on a parchment-lined tray and pop them in the freezer for an hour. This step matters more than you’d think, frozen marshmallows hold their shape much better in the oven instead of melting into a sticky puddle throughout the dough. Sometimes if you don’t freeze them, the marshmallows will literally dissolve into the cookie itself and then you’re left with no ooey gooeyness.

Brown the Butter

In a medium saucepan over medium heat, add your butter and let it cook, swirling the pan occasionally. It’ll melt, then foam up, and eventually turn a deep golden brown with a nutty aroma, this takes about 5 to 7 minutes. Keep a close eye on it toward the end since it can go from perfectly browned to burnt fast.

Once it’s browned, pour it into a heatproof bowl and let it cool in the fridge just until it reaches room temperature, about 10 minutes. It should still be liquid, not solid, at this point.

🤎 TIP: If your butter is too hot when you start creaming it with the sugars, it can throw off the texture of the dough and even start to cook your eggs once they’re added, so don’t rush this cooling step.

Make the Dough

In a large bowl, add your cooled brown butter along with the light brown sugar and granulated sugar. Using a hand mixer or a whisk, cream everything together until smooth. Add your eggs and vanilla extract and mix until fully incorporated.

In a separate bowl, whisk together your flour, baking soda, and salt. Add the dry ingredients into the wet ingredients and mix until just combined, you don’t want to overwork the dough here, just mix until you don’t see any more streaks of flour.

Finally, fold in your rice krispies cereal and frozen mini marshmallows until they’re evenly distributed throughout the dough.

Bake the Cookies

Preheat your oven to 350°F and line a baking sheet with parchment paper. Using a 1/4 cup scoop, portion out the dough onto your prepared sheet, spacing each mound about 2 inches apart. If you like a flatter cookie, gently press each one down a bit with your palm before it goes in the oven.

Bake for 10 to 12 minutes, until the edges are set and just starting to turn golden. As soon as they come out of the oven, use a spatula to gently press each cookie down for an even, flat top. Let them cool on the baking sheet for about 15 minutes, and they should be ready to enjoy right after that.

Tips & Variations

• Freezing the marshmallows is non-negotiable if you want them to hold their shape instead of melting away.
• Press the cookies down before baking if you like a flatter, more spread-out cookie.
• Don’t skip cooling the browned butter, using it too hot will affect the texture of your dough.
• Store extras in an airtight container at room temperature for up to 4 days.

Troubleshooting

• My cookies came out too flat. This usually means your butter was too warm when it went into the dough, or your dough sat out too long before baking. Make sure your browned butter has cooled properly before creaming it with the sugars.

• My cookies are too dark on the bottom. This is usually an oven or pan issue rather than the recipe itself. Dark or thin baking sheets conduct heat faster and can scorch the bottoms before the tops finish baking, so a light-colored, heavy-duty sheet works best. Also double check your oven temperature with an oven thermometer, since many run hotter than what the dial says, and try moving your rack to the middle position if it’s sitting too low.

• My marshmallows melted everywhere instead of staying in pockets. This almost always comes down to skipping the freezer step. Make sure your marshmallows are fully frozen solid before folding them into the dough.

• My cookies are dry or crumbly. This can happen from overmixing the dough once the flour is added, or from overbaking. Mix just until the flour disappears, and pull the cookies out as soon as the edges are set, even if the centers still look a little soft.

• My cookies spread too thin. This usually points to butter that was too warm, dough that sat out too long before baking, or too little flour measured out. Spoon and level your flour instead of scooping directly from the bag to avoid packing in too little.

Craving more like this? Try these recipes out!

• S’mores Brownie Cookies – Crumbl Copycat — a rich, fudgy copycat cookie loaded with graham crackers and gooey marshmallow.
• Chocolate Chip Cookies — a classic browned butter chocolate chip cookie with pools of melty chocolate in every bite.
• Cookies & Cream Cookies — soft, chewy cookies loaded with crushed Oreos and both white and semi-sweet chocolate chips.
• Cinnamon Roll Cookies — a soft sugar cookie swirled with caramelized cinnamon sugar and topped with a vanilla glaze.
• Levain Style Cookies n Creme Cookies — massive, fudgy NYC-style bakery cookies with a cookies and creme twist.

If you make this recipe, make sure to leave a comment below and let me know how it turns out — I love hearing from you! And if you snap a photo, don’t forget to tag me over on Instagram or TikTok so I can see your creations too.

You can also find this recipe and so many more on my Pinterest — perfect for saving to your board for later. And if you’re more of a visual learner, check out my YouTube channel, where I walk you through recipes step-by-step just like this one.