Brown Butter Rice Cereal Marshmallow Cookies

These Brown Butter Rice Cereal Marshmallow Cookies are a playful mashup of toasted, nutty brown butter and the childhood comfort of crispy rice cereal and mini marshmallows. The cookies bake up tender at the center with crisped edges, studded with airy marshmallows that soften but keep some chew. The browned butter gives a warm, caramelized aroma and a complex, toasty flavor that lifts the simple sweetness. Texture is key here: the light crunch of the cereal contrasts with gooey, pillowy marshmallow pockets for an irresistible bite.

They are ideal for cookie swaps, after-school treats, or anytime you want a nostalgic yet grown-up cookie. Make them when you want something quick to freeze and bake off later, or plate them warm for a cozy dessert with milk or coffee. The optional flaky sea salt on top makes the sweet and nutty flavors pop.

Ingredients

1 cup unsalted butter, cut into 16 pieces
Use unsalted so you control the salt level, and cut into pieces to help the butter brown evenly.
2 and 1/4 cups all-purpose flour
The structure of the cookie, measured by volume for a tender bite.
2 teaspoons cornstarch
Keeps the cookies tender and gives a soft, slightly shortbread-like texture.
1 teaspoon baking soda
Provides lift and helps the cookies spread properly.
1/2 teaspoon salt
Balances sweetness and enhances the brown butter flavor.
2 cups crispy rice cereal
Adds light crunch and that classic cereal texture.
1 cup mini marshmallows
Small marshmallows melt and create soft, chewy pockets in the cookies.
3/4 cup packed light or dark brown sugar
Offers moisture and a rich, caramel note; dark will give deeper flavor, light will be milder.
1/2 cup granulated sugar
Adds sweetness and helps with spreading and browning.
1 large egg, at room temperature
Adds structure and helps bind the dough.
1 large egg yolk, at room temperature
Extra yolk increases tenderness and chew.
2 teaspoons pure vanilla extract
Rounds out the flavors with warm, sweet aromatics.
Optional: flaky sea salt, for topping
Sprinkle a little on top after baking for a salty contrast.

Step-by-step Instructions

Brown the butter. In a light-colored skillet or saucepan over medium heat, melt the butter while stirring constantly. After 5 to 8 minutes, the butter will turn brown and smell nutty. Watch carefully so it does not burn. Pour the browned butter into a bowl and set aside to cool slightly.
Whisk dry ingredients. In a large bowl, whisk together the all-purpose flour, cornstarch, baking soda, and salt until evenly combined.
Fold in cereal and marshmallows. Add the 2 cups crispy rice cereal and 1 cup mini marshmallows to the dry mixture and fold gently so they are evenly distributed.
Combine wet ingredients. In another bowl, whisk the cooled brown butter, 3/4 cup packed brown sugar, 1/2 cup granulated sugar, the large egg, the large egg yolk, and 2 teaspoons pure vanilla extract until combined and smooth.
Make the dough. Pour the wet mixture into the bowl with the dry ingredients and stir until everything is incorporated and a sticky dough forms.
Form the cookies. Scoop about 2 tablespoons of dough and roll it into balls. Place the dough balls on a tray and freeze for 1 hour. Freezing helps the cookies retain a thick center when baked.
Preheat and prepare pans. Preheat the oven to 350°F (177°C). Line baking sheets with parchment paper.
Bake. Arrange the frozen dough balls 3 inches apart on the prepared baking sheets. Bake for 14 to 15 minutes, until the cookies are lightly browned around the edges.
Finish and cool. If using, sprinkle flaky sea salt on top immediately after removing the cookies from the oven. Cool on the baking sheet for 10 minutes before transferring to a cooling rack to finish cooling.

Recipe Details

Prep Time: 20 minutes active, plus 1 hour freezing
Cook Time: 14 to 15 minutes per batch
Total Time: About 1 hour and 35 minutes including freezing and cooling
Servings: Makes about 24 cookies (using 2 tablespoons of dough per cookie)
Calories: Approximately 175 kcal per cookie

Tips, Storage & Variations

Tips

Let the browned butter cool slightly before mixing with eggs to avoid scrambling them.
Freeze dough balls as directed for consistent shape and a chewy center.
Use a light-colored pan for browning butter so you can monitor the color change.

Storage

At room temperature: Store cooled cookies in an airtight container for up to 3 days.
Refrigerate: Keep in an airtight container for up to 1 week.
Freeze: Freeze baked cookies in a single layer on a baking sheet, then transfer to a freezer bag for up to 3 months. Thaw at room temperature.
Freeze dough: Keep frozen dough balls in a single layer for up to 1 month, then bake from frozen, adding a minute or two to the bake time if needed.

Variations using the existing ingredients

Dark brown sugar for deeper caramel notes, or light brown sugar for a milder caramel flavor.
Increase marshmallows slightly for extra gooey pockets, or reduce for more cereal crunch.
Finish with flaky sea salt for a salted-sweet contrast, or skip the salt for a purely sweet cookie.

Brown Butter Rice Cereal Marshmallow Cookies

FAQ

How do I know when the brown butter is done?
The butter will foam, then the milk solids will turn golden brown and it will smell nutty. Remove from heat as soon as you see brown specks.
Can I skip freezing the dough?
You can, but freezing helps the cookies keep a thick, chewy center and improves texture and shape.
Will the mini marshmallows melt completely?
Mini marshmallows will soften and create chewy pockets, but they will not completely disappear.
Can I use salted butter instead of unsalted?
Yes, but reduce or omit the added 1/2 teaspoon salt to avoid an overly salty cookie.
How do I prevent the marshmallows from browning too much?
Watch the final minutes of baking and tent the cookies with foil if the marshmallows start to brown too quickly.
Can I make the dough ahead of time?
Yes, freeze the formed dough balls for up to 1 month and bake from frozen when ready.

Conclusion

I hope you enjoy baking these Brown Butter Rice Cereal Marshmallow Cookies as much as I enjoyed developing the recipe. They are a comforting mix of toasty brown butter, chewy marshmallow pockets, and delicate cereal crunch that make for a memorable homemade treat. If you like variations with extra gooey rice crispies or nostalgic marshmallow bites, these cookies are a perfect canvas.

For a similar marshmallow cookie inspiration, check out this take on crispy marshmallow cookies at Marshmallow Crispy Cookies (Costco Copycat) – The Salted Sweets, and for another brown butter spin on rice crispies see Brown Butter Rice Crispy Treats (Extra Gooey & Chewy!). Share your results and any little tweaks you make, and enjoy a warm cookie with a cozy cup of something you love.