This no bake treat is one of my longtime favorites because it always turns out perfectly. The chewy, buttery cornflake base is mixed with creamy peanut butter and gooey marshmallows, then finished with a smooth layer of dark chocolate that gives it that perfect snap once it sets.

I’ve tested this recipe so many times over the years, and it’s never failed me! It’s simple, nostalgic, and made with ingredients you probably already have on hand. Whether you’re packing lunch boxes, planning a party, or just craving something sweet and homemade, this is the kind of foolproof recipe you’ll want to make again and again.
These are like my cornflake caramels! They're the go to treat if you need a quick pick-me-up. Check out my pistachio white chocolate blondies , peanut butter and chocolate rice krispies bars, and s mores blondies as well!
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Why you'll love this Cornflake Slice recipe
- Peanut Butter Cornflake Flavor: Rich, nutty taste of peanut butter perfectly complemented by the crunchy texture of cornflakes. This corn flake slice recipe combines these two beloved flavors to create a taste that's utterly addictive.
- Chewiness from the Marshmallows: The marshmallows in this recipe add an amazing chewiness like my chocolate covered rice krispies that takes these to the next level.
- Ease of Making Them: One of the best things about this recipe is just how easy it is to make. With simple ingredients and straightforward instructions, anyone can whip up a batch of these delicious slices in no time. edible Biscoff cookie dough is also no bake!!
Equipment
Large Pot will make your life much easier! The cornflakes will go everywhere if your pot isn't big enough when stirring everything together trying to get it completely combined.
Cornflake Slices Ingredients

- Smooth and Creamy Peanut Butter (Not Natural): Smooth and creamy peanut butter is ideal for this recipe. Unlike natural peanut butter, which tends to separate and can have a gritty texture, smooth and creamy peanut butter blends seamlessly with the other ingredients.
- Regular and Unsweetened Cornflakes: Regular, unsweetened cornflakes are preferred for this recipe to maintain the balance of flavors and textures. Sweetened cornflakes may result in overly sweet flavor, overpowering the natural sweetness of the marshmallows and dark chocolate topping. I like Kellog's. Don't use honey cornflakes.
- Original Marshmallows (Not Vegan): Original marshmallows, which contain gelatin derived from animal sources, are traditionally used in this recipe for their classic flavor and texture. These marshmallows melt smoothly and evenly, creating a chewy texture. Chocolate ice cream with marshmallow is amazing too!!
See recipe card for quantities.
Cornflake Slice Ingredients
- Brown the butter for extra nutty goodness! Brown butter makes everything better. It would be amazing in these corn flake squares. Brown butter blondies are so good.
- Honey in these would be amazing, honey cornflake flavor is very nostalgic and would go so well with cornflake marshmallow.
- Skip the chocolate on top if you're not a fan, but don't skip finishing them with flaky sea salt.
- If you want more crunch and texture, chopped up peanuts on top of the chocolate would be incredible!
This recipe has not been tested with other substitutions. These are just suggestions.
How to make Cornflake Marshmallow Treats

Step 1: Line an 8X8 pan with parchment paper.

Step 2: In a large pot over medium heat, melt the butter and marshmallows. Stirring until completely melted.

Step 3: Take the pot off of the heat. Add the peanut butter, mix until combined and melted.

Step 4: Pour in the cornflakes, Mix until almost combined, pour in the mini marshmallows. Mix until completely combined and coated.

Step 5: Pour into the parchment lined pan. Spread it out evenly, making sure to push it down a bit to get into the corners of the pan.

Step 6: Pour the melted chocolate over the top, spreading it out evenly. Place in the refrigerator until the chocolate is set. Take out and top with flaky sea salt. Cut into bars and enjoy!
Hint: Top with flaky sea salt before eating, it makes the flavors pop and cuts the sweetness!
Cornflake Slice Pro tips
- When mixing the marshmallows into the cornflake and peanut butter mixture, reserve 1 cup of marshmallows and gently fold them in at the end. This ensures you have pockets of gooey marshmallow goodness throughout the slices.
- Line the baking pan with parchment paper before pressing the mixture into it. This not only prevents the slices from sticking to the pan but also makes cleanup a breeze. Once the mixture is in the pan, use the parchment paper to press it down evenly and compactly. .
- Opt for dark chocolate when preparing the topping to balance out the sweetness of the marshmallows and peanut butter. The slight bitterness of dark chocolate complements the sweetness of the other ingredients, creating a more satisfying flavor profile.
Cornflake Slice FAQs
How can I store these?
Place the slices in an airtight container or sealable plastic bag to prevent them from drying out. Store the container at room temperature, away from direct sunlight or heat sources. Enjoy within 5 days for optimal freshness and flavor.
Can I double the recipe?
Yes! You can use a 9X13 pan and just double all of the ingredients.
Is this recipe gluten free?
You can try to find gluten free Cornflakes! Always check all of the other ingredients for gluten as well.

Storage
Room Temperature
Place the slices in an airtight container or sealable plastic bag to prevent them from drying out. Store the container at room temperature, away from direct sunlight or heat sources. Enjoy within 5 days for optimal freshness and flavor.
Refrigeration
It's best not to refrigerate the slices, as this can alter their texture and make them overly firm or dry. Keep them at room temperature for the best taste and texture.
Freezer
If you'd like to extend the shelf life, you can freeze the slices. Place them in an airtight container, separating layers with parchment paper to prevent sticking. When ready to enjoy, thaw the slices in the refrigerator overnight or at room temperature for a few hours.
Related
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📖 Recipe

Cornflake Slices
Equipment
- 8X8 baking pan
- Large metal pot
- Mixing bowls
- Measuring Cups
- Rubber Spatula
Ingredients
- 5 tablespoons (71 grams) salted butter
- 5 cups (283 grams) marshmallows for melting
- ½ cup plus 2 tablespoons (157 grams) peanut butter creamy, not natural (I like Skippy)
- 4.5 cups (161 grams) Cornflakes cereal unsweetened (I like Kellog's)
- 1 cup (62 grams) mini marshmallows do not melt
Topping
- 1 cup (166 grams) dark chocolate melted
Instructions
- Line an 8X8 pan with parchment paper. In a large pot over medium heat, melt the butter and marshmallows. Stirring until completely melted.
- Take the pot off of the heat. Add the peanut butter, mix until combined and melted.
- Pour in the cornflakes, Mix until almost combined, pour in the mini marshmallows. Mix until completely combined and coated.
- Pour into the parchment lined pan. Spread it out evenly, making sure to push it down a bit to get into the corners of the pan.
- Pour the melted chocolate over the top, spreading it out evenly. Place in the refrigerator until the chocolate is set. Take out and top with flaky sea salt.
- Cut into bars and enjoy!










Kelsey says
Oh my gosh these were such a hit!
Amanda says
so happy to hear it!! 🙂
Nicolette says
Okay, listen. I was craving something sweet so I went to the store with a sort-of vision. My mom makes Special K bars, I really like Rice Krispie (?) bars, I don't know but I got corn flakes, marshmallows, and chocolate. Wasn't sure where I was going.
I went to the internet and said listen up, here's what I've got, what can I do. I was presented with this recipe. Peanut butter? Got that on hand. Made this. Could NOT have been happier. Couldn't keep my hands off it. Husband told me I'm not allowed to make it again because he is trying to lose weight (he's weird about sugar, I'm going to make this 10k times).
Told my grandma about this since I'm visiting her soon. She said if I didn't come with these bars she would excommunicate me (she did not say this but she is very excited for the bars). Recipe with almost no reviews? Who cares. I made it because those are the ingredients I had and these beat any and every family reunion bar I have ever had. Will be making forever and always so THANKS.
Am I one hundred years old? Nah just 30 but dang when a bar does you this good you gotta leave a review. Thanks again!
Amanda says
Oh my gosh this review made my day!!! Best comment EVER! Thanks for the laugh, I'm so glad everyone enjoyed them, thrilled you'll be sharing with your grandma too 🙂 Happy Holidays