Marshmallow Rice Krispy Cookies start crisp, melt in the middle, and hit you with that nostalgic Rice Krispie Treat vibe — but in cookie form. Imagine browned butter caramel notes, crunchy Rice Krispies, and chewy mini marshmallows all hanging out in one thin, buttery cookie. Sound dangerous? It absolutely is — in the best possible way.
Why you’ll love this recipe
These cookies are fun, flattering, and stupidly easy to make. They deliver that exact Rice Krispie-meets-cookie experience Costco made famous, but fresher and more caramel-forward because we use browned butter. If you love Krispy Cookies or anything that tastes like a childhood snack upgraded for adults, this recipe is your new go-to.
Quick hits:
- No chilling required. Scoop — bake — eat.
- Better than the store: Fresh browned butter takes these past the Costco Marshmallow Crispy Cookies level.
- Texture party: crisp edges, chewy center, marshmallow pockets, Rice Krispy crunch.
The (very short) story behind these cookies
I kept getting requests to recreate that Costco cookie — and honestly, I love any project that’s basically adult nostalgia. After a few tests (and a lot of taste-testing), brown butter stole the show. The toasty, caramel notes make these more than a copycat — they’re the grown-up cousin of a Marshmallow Rice Crispy Cookies classic.
Ingredient breakdown (and why each one matters)
- Brown butter (½ cup before browning): This is the flavor MVP. Browning deepens the butter into caramel-y goodness. Pro tip: don’t walk away — it goes from perfect to burnt in seconds.
- Granulated + brown sugar: Granulated gives structure; brown sugar brings chew and depth.
- All-purpose flour: The base. Spoon & level if you measure by cups, or use grams for best accuracy.
- Baking soda + salt: Lift and balance. I finish with a pinch of flaked salt on each cookie — do it.
- Egg + vanilla: Binder and flavor booster.
- Rice Krispies: For that signature crunch — the reason we call them Rice Krispie Marshmallow Cookies sometimes.
- Mini marshmallows: They melt into gooey pockets. Use mini for even distribution.
- Optional butterscotch chips: If you want a butterscotch twist (think Butterscotch Marshmallow Cookies), toss some in.
Marshmallow Rice Krispy Cookies — Step-by-step method
Follow this exactly for best results.
- Brown the butter. Melt butter in a light-colored saucepan over medium. It will foam, then the foam subsides and brown bits appear. Smell for nutty aroma. Immediately transfer to a heatproof bowl and chill 8–10 minutes to firm slightly. Browned butter = flavor jackpot.
- Mix wet ingredients. In a medium bowl whisk the cooled brown butter with both sugars until smooth. Add egg and vanilla; mix until glossy.
- Add dry. Stir in flour, baking soda, and a pinch of salt. Mix just until combined — don’t overwork.
- Fold in crunch & chew. Gently fold Rice Krispies, then mini marshmallows. The marshmallows will be soft; fold carefully so they don’t explode.
- Scoop big. Use a 3-tablespoon scoop or form large (50–60 g) dough balls. These spread thin — place 4–5 per sheet.
- Bake. 350°F (175°C) for 10–13 minutes. Edges should be light golden; centers still soft. Overbaking kills chew.
- Finish. Right out of the oven, sprinkle with flaky salt. Let cool on the sheet 5 minutes, then transfer to a rack.
Expert baking tips (aka things I learned the annoying way)
- Watch the butter while browning. Stir constantly and pull it off when it smells nutty and looks amber.
- Cool the brown butter slightly — too hot and you’ll melt your marshmallows before they hit the oven.
- Use mini marshmallows for even pockets of goo. Jumbo = weird blobs.
- If dough looks wet, add 2–3 tablespoons flour for slightly thicker cookies. This keeps them from turning into crisps only.
- Scoop large balls for the best thin-crispy/chewy balance. Small cookies will be too dense.
- Flaked salt on top takes them from “yum” to “wow.” Don’t skip it.
- For gluten-free, sub a 1:1 GF flour and gf Rice Krispies to make a Marshmallow Rice Crispy Cookies GF version.
Variations to try
- Butterscotch twist: Add ¼ cup butterscotch chips — hello, Butterscotch Marshmallow Cookies.
- Chocolate lovers: Toss in ½ cup mini choc chips or use cocoa in the dough for an ultra-chocolate Rice Krispie Marshmallow Cookies.
- Peanut butter: Swirl ¼ cup peanut butter into the wet mix before adding dry ingredients. PB + marshmallow = PB&J nostalgia.
- No-marshmallow option: Omit marshmallows and add extra cereal + a handful of chips — gives you a purely crunchy Krispy Cookies version.
- Toast marshmallows: Lightly toast mini marshmallows with a kitchen torch before folding in for a smoky marshmallow hit.
Best ways to serve these cookies
- Straight up: Warm from the oven with a cold glass of milk. Iconic.
- Cookie sandwiches: Add a scoop of vanilla ice cream between two cookies — instant party.
- Dessert board: Add a few cookies to a board with brownies, fruit, and nuts for gatherings.
- Gifts: Stack 3–4 in cellophane, tie with a ribbon — these keep people very happy.
Storage & freezing (because leftovers matter)
- Room temp: Airtight container for 2–3 days. Tip: put a slice of bread in the container to maintain chew.
- Freeze baked cookies: Flash-freeze on a tray then transfer to a freezer bag for up to 3 months. Thaw at room temp or warm in a 300°F oven for 3–5 minutes.
- Freeze dough balls: Freeze raw scoops on a tray. Once solid, store in a freezer bag. Bake from frozen at 325°F for a couple minutes longer.
FAQ (short & punchy)
Can I skip browning the butter?
Yes, but brown butter gives caramel depth that makes these better than basic Marshmellow Cookie Recipe attempts. FYI: it’s worth the 5 minutes.
Do marshmallows melt into a mess?
They soften and create chewy pockets. If you hate spreading, chill the dough briefly and use fewer marshmallows.
Can I use cereal other than Rice Krispies?
Rice Krispies give the classic crunch. Feel free to experiment, but texture will change.
How do I stop the cookies from flattening too much?
Add 2–3 tbsp more flour, chill dough 15–20 minutes, and don’t overbake.
Is this recipe basically the Costco cookie?
Very similar — but with brown butter and flaked salt, these taste even better IMO.
Quick pro check before baking
- Preheat oven and line pans.
- Don’t overcrowd a sheet — they spread.
- Take them out when edges are gold but centers still soft.
Final thoughts — the short version
These Marshmallow Rice Krispy Cookies are crunchy, chewy, buttery, and nostalgic. They’re a fun hybrid between cookies and Rice Krispie treats — and yes, they beat the Costco Marshmallow Crispy Cookies in a straight-up taste-off (I said it). Whether you’re baking for a crowd, packing school lunches, or making midnight snacks, these cookies will disappear fast.
Give them a go, and if you want a riff for chocoholics, butterscotch fans, or a gluten-free version — I got you.
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Ultimate Marshmallow Rice Krispy Cookies — An Irresistible Twist On Classic Krispy Cookies
- Prep Time: 25 minutes
- Cook Time: 11 minutes
- Total Time: 36 minutes
- Yield: 13 servings 1x
- Category: Dessert
Description
A buttery, brown-butter cookie studded with Rice Krispies and chewy mini marshmallows. Thin, crunchy at the edges, gooey in the middle — no chilling needed and super quick to pull together.
Ingredients
- ½ cup (113.5 g) salted butter
- ¾ cup (165 g) packed brown sugar
- ½ cup (100 g) granulated sugar
- 1 large egg, at room temperature
- 1 teaspoon vanilla (vanilla paste works great here)
- ½ teaspoon baking soda
- ¾ teaspoon fine salt
- 1 cup (140 g) all-purpose flour
- 1½ cups (43 g) Rice Krispies cereal
- ⅔ cup (30 g) mini marshmallows
- Flaky sea salt, for sprinkling
Instructions
- Preheat the oven to 350°F (175°C) and line a baking sheet with parchment.
- Brown the butter: melt the butter in a light-colored saucepan over medium heat. Let it foam, then keep cooking while stirring until it turns a warm amber color and gives off a toasty, nutty aroma. Watch closely — it changes quickly. Pour the browned butter into a heatproof bowl and chill briefly (about 8–12 minutes) so it cools but remains pourable.
- In a medium bowl whisk the cooled browned butter with both sugars until smooth. Add the egg and vanilla and mix on low just until combined.
- Add the baking soda, salt, and flour and fold in gently until the dough comes together. Avoid overmixing.
- Fold in the Rice Krispies, then gently fold in the mini marshmallows. The marshmallows will soften — handle the dough with care.
- Using a 3-tablespoon scoop (or spoon), portion dough into large balls and place them spaced well on the prepared sheet (4–5 per sheet works well since these spread).
- Bake 10–13 minutes, until the edges are lightly golden but the centers still look a tad soft. Don’t overbake if you want that chewy center. Immediately sprinkle each warm cookie with flaky sea salt.
- Let cool on the baking sheet 5 minutes, then transfer to a wire rack to finish cooling.
Notes
- These cookies are intentionally thin and buttery. If you prefer a thicker cookie, add 2 tablespoons more flour.
- Measuring by weight yields the most consistent results — grams are more precise, especially for flour. If you use cups, spoon the flour into the cup and level it rather than scooping.
- If you’re in a hurry, you can skip cooling the browned butter long; just don’t use it piping hot or it will melt the marshmallows too much.
- Store baked cookies in an airtight container at room temperature for 2–3 days. Dough balls can be frozen and baked from frozen (add a couple minutes to baking time).
Nutrition
- Calories: 202kcal
- Sugar: 22g
- Sodium: 261mg
- Fat: 8g
- Saturated Fat: 5g
- Trans Fat: 0.3g
- Carbohydrates: 32g
- Fiber: 0.3g
- Protein: 2g
- Cholesterol: 33mg
