No-Bake Peanut Butter Marshmallow Cornflake Cookies

The Magical, No-Fuss Cookie That Tastes Like a Hug

Hey there, my fellow flavor adventurer! Let’s be real: sometimes, you just need a cookie. Not a cookie that requires a degree in pastry arts, a mountain of dirty bowls, or the patience to wait for the oven to preheat. You need a cookie that comes together in the time it takes to watch your favorite sitcom, a cookie that requires exactly zero baking skills, but delivers maximum, soul-satisfying joy.

That, my friend, is the magic of these No-Bake Peanut Butter Marshmallow Cornflake Cookies. We’re talking a trifecta of glorious textures: the crispy-crunch of cornflakes, the impossibly gooey, sweet melt of marshmallows, and the rich, salty-smooth embrace of peanut butter. It’s a childhood classic, but we’re not stopping there. We’re taking it to a whole new level with a double batch (because sharing is caring, but also… because we want extra), a flurry of white chocolate chips, and a sophisticated kiss of flaky sea salt. This is the kind of treat that makes you feel like a kitchen wizard with minimal effort. So, grab your biggest pot and your favorite spoon—we’re about to make some magic happen.

My Grandmother’s Stovetop Cookie Legacy

This recipe whisks me right back to my grandmother’s linoleum-floored kitchen, a place that always smelled like a beautiful collision of brewing coffee and something sweet. She was the queen of “eyeballing it,” a fearless culinary artist who believed recipes were mere suggestions. Her version of these cookies was a humble, three-ingredient affair: cereal, peanut butter, and marshmallows. No measurements, just feeling.

I’d perch on a stool, watching her strong hands stir the bubbling, glossy marshmallow mixture, my job being the official “cornflake incorporator.” She’d always let me sneak a spoonful of the warm, gooey mix, a secret treat that felt like stolen sunshine. Those cookies weren’t just a dessert; they were a lesson in improvisation, in the simple joy of creating something delicious with what you have. My version is a loving tribute to hers—a little fancier, maybe, with its drizzles and sea salt, but with the same heart: effortless, joyful, and meant to be shared with someone you love.

No-Bake Peanut Butter Marshmallow Cornflake Cookies

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• Author: clarawhitmore
• Yield: ~20 large cookies

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Description

These no-bake cookies are chewy, crunchy, and packed with gooey marshmallow and peanut butter flavor—perfect for quick treats or holiday platters. We doubled the batch for sharing and added white chocolate and a pinch of sea salt to take them to the next level.

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Ingredients

Scale 1x2x3x

8 tbsp salted butter

1½ cups smooth peanut butter

20 oz mini marshmallows (reserve 2 oz for mixing in)

⅔ cup peanut butter chips (plus ¼ cup for drizzle)

14 cups cornflakes

½ tsp flaky sea salt (optional twist)

⅓ cup white chocolate chips (optional twist)

1 tsp vegetable oil (for drizzling)

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Instructions

In a large pot over medium heat, melt butter and peanut butter until smooth.

Stir in 18 oz marshmallows and melt completely. Remove from heat.

Mix in cornflakes, stirring to coat evenly.

Gently fold in 2 oz marshmallows, white chocolate chips, and sea salt.

Scoop into mounds on a parchment-lined tray.

Melt remaining peanut butter chips with oil. Drizzle over cookies.

Let set at room temp for 30 mins or chill briefly to speed it up.

• Category: Dessert

Nutrition

• Calories: 220
• Fat: 10g
• Carbohydrates: 30g
• Protein: 3g

Gathering Your Cookie Crew: The Ingredients

Here’s the dream team! The beauty of this recipe is its flexibility, so I’ve included my favorite chef insights and swaps to make it your own.

• 8 tbsp (1 stick) Salted Butter: This is our rich, creamy base. Salted butter adds a lovely depth that balances the sweetness. Chef’s Insight: If you only have unsalted, just add an extra pinch of salt to the mixture!
• 1½ cups Smooth Peanut Butter: The star of the show! Use a conventional brand like Jif or Skippy for the best texture and sweetness. The oils are stabilized, making for a perfect, smooth melt. Sub Tip: For a natural twist, use a well-stirred natural peanut butter, but know the texture might be a bit oilier and the flavor less sweet.
• 20 oz Mini Marshmallows: Our sticky, glorious glue. Minis melt down evenly and quickly. We’re reserving 2 oz to fold in at the end for those incredible, gooey pockets! Chef’s Hack: To prevent a sticky nightmare, give your measuring cup or spoon a quick spritz of cooking spray.
• ⅔ cup + ¼ cup Peanut Butter Chips: A double dose of peanut buttery goodness! The ⅔ cup gets mixed in, and the ¼ cup is for that gorgeous drizzle on top.
• 14 cups Cornflakes: The crunch factor! This seems like a lot, but they compress down. Sub Tip: Feel free to swap in any crispy cereal like Rice Krispies or even a flakey bran cereal for a different texture.
• ½ tsp Flaky Sea Salt (optional but highly recommended): This is our secret weapon! A pinch of flaky salt sprinkled into the mix and on top at the end cuts through the sweetness and makes every flavor pop.
• ⅓ cup White Chocolate Chips (optional twist): My fancy-pants addition. They add little creamy, sweet bursts that pair amazingly with the peanut butter.
• 1 tsp Vegetable Oil (for drizzling): Just a tiny bit mixed with the peanut butter chips to make a smooth, drizzle-able glaze.

Let’s Get Sticky: The Step-by-Step Magic

Ready? This is the fun part. Put on some music, and let’s do this!

1. Melt the Foundation: In your largest pot or Dutch oven, melt the butter and peanut butter together over medium heat. Stir it constantly with a sturdy wooden spoon or silicone spatula until it’s one smooth, dreamy, fragrant liquid. This should only take 2-3 minutes. Don’t walk away! We’re building flavor, not burning it. Chef’s Tip: Using a light-colored pot helps you see the color change and avoid scorching.
2. Marshmallow Cloud Time: Now, dump in 18 oz of the mini marshmallows. Reduce the heat to low. Keep stirring! It will look voluminous and chaotic at first, but soon the marshmallows will melt down into a smooth, thick, glossy lava. This is the key to perfect cookies—you want every last marshmallow bit to be melted. Once it’s completely smooth, remove the pot from the heat immediately. Chef’s Hack: A tiny pat of butter on your spoon or spatula helps prevent the marshmallow from sticking to it like glue.
3. The Big Fold: Time for the cornflakes! Pour all 14 cups into the pot. Using a gentle folding motion, stir and turn the mixture until every single cornflake is thoroughly coated in the peanut butter marshmallow goodness. It’s an arm workout! You’ll know it’s ready when no dry cereal remains. Chef’s Note: Be gentle yet thorough. We want to coat everything without crushing all the flakes into dust.
4. Add the Fun Mix-Ins: Now, for the textural magic. Gently fold in the reserved 2 oz of mini marshmallows, the white chocolate chips (if using), and that pinch of flaky sea salt. This gives you wonderful little pockets of different flavors and textures in every single bite.
5. Scoop & Shape: Line two large baking sheets with parchment paper. Using a generously sized cookie scoop or a ¼ cup measure, drop mounds of the mixture onto the sheets. Work relatively quickly as the mixture will start to set. If you want a more uniform shape, lightly dampen your hands and press the mounds together. They won’t spread, so you can place them fairly close together. Chef’s Tip: For a beautiful finish, don’t press them down flat. Leave them as rustic, craggy mounds.
6. The Fancy Drizzle: In a small microwave-safe bowl, combine the ¼ cup of peanut butter chips with the 1 tsp of vegetable oil. Microwave in 20-second bursts, stirring in between, until completely smooth. Using a fork or a small piping bag, drizzle this glorious glaze over each cookie mound. Finish with another tiny sprinkle of flaky sea salt on top for that professional bakery touch.
7. The (Hardest Part) Wait: Let the cookies set at room temperature for at least 30 minutes. If you’re impatient (hello, me!), you can pop the trays into the refrigerator for 15 minutes to speed up the process. They are ready when they hold their shape and are firm to the touch.

How to Serve These Glorious Mounds

These cookies are stars all on their own! Pile them high on a rustic wooden board or a cute vintage platter for a seriously impressive dessert spread. They’re the perfect potluck hero because they travel like a dream. For the ultimate experience, serve them alongside a cold glass of milk, a hot coffee, or even a dunkable hot chocolate. They’re rich, so one is usually plenty… but I won’t judge if you sneak a second.

Mix It Up! Creative Twists & Swaps

• Chocolate Lover’s Dream: Swap the white chocolate chips for semi-sweet or dark chocolate chips. You could even drizzle with melted dark chocolate instead of peanut butter.
• Nut-Free Nirvana: Use sunflower seed butter instead of peanut butter and omit the peanut butter chips. The flavor will be different but still delicious!
• Trail Mix Twist: Fold in ½ cup of chopped pretzels and ½ cup of dried cranberries along with the cereal for a sweet-and-salty situation.
• Triple Chocolate: Use chocolate cornflakes or Cocoa Pebbles, mix in chocolate chips, and drizzle with chocolate.
• Almond Joy: Use almond butter, fold in shredded coconut and dark chocolate chips, and drizzle with more melted chocolate.

Clara’s Chef Notes & Kitchen Confessions

This recipe has evolved so much from my grandmother’s simple version, and I love that. I’ve learned a few things along the way: First, the size of your pot matters. USE THE BIGGEST ONE YOU HAVE. I cannot stress this enough. Trying to mix 14 cups of cereal in a medium saucepan is a recipe for a flaky, sticky floor disaster. Trust me, I’ve been there.

Second, these cookies are forgiving. If your mixture seems too dry, add a touch more melted peanut butter. Too wet? A handful more cereal will fix it. It’s all about feeling, just like my grandma taught me. Finally, these make fantastic food gifts! Package a few in a cellophane bag tied with a ribbon, and you’ve just become everyone’s favorite person.

Your Questions, Answered!

• Q: My cookies turned out really hard. What happened?

  A: This usually means the marshmallow mixture was cooked for too long or over too high heat. It can cause the sugars to harden more. Next time, keep the heat to medium-low and remove the pot from the heat the second the marshmallows are fully melted.

• Q: Can I use marshmallow fluff instead of mini marshmallows?

  A: You can! Substitute the 18 oz of melting marshmallows with a 16 oz jar of marshmallow fluff (the same weight, just in a different form). The texture will be slightly different, but it will still work. You’ll still want to fold in the mini marshmallows at the end for texture.

• Q: How should I store these, and how long do they last?

  A: Store them in an airtight container at room temperature for up to 5 days. They might get a little softer over time, but they’ll still be delicious. You can also layer them between sheets of parchment paper so they don’t stick together.

• Q: My mixture was impossible to stir! Did I do something wrong?

  A: It’s a thick mixture! This is why a large pot and a sturdy utensil are non-negotiable. If it becomes unmanageable, you can briefly take it off the heat to stir with more leverage, or enlist a helper to hold the pot steady while you fold.

Quick Nutritional Note

While these are a treat, it’s helpful to know what you’re enjoying! This approximate info is per cookie (based on yielding 20 large cookies): 220 calories | 10g fat | 30g carbs | 3g protein. Remember, these are estimates and can vary based on your specific ingredients and portion sizes.