If you want an easy, crowd-pleasing treat that requires no oven time, these no-bake peanut butter cornflake bars are a winner. They combine crunchy cornflakes, a gooey peanut-buttery marshmallow base and a smooth chocolate topping for the perfect balance of crunchy, chewy and chocolaty. The recipe uses only five straightforward ingredients: cornflakes, peanut butter, marshmallows, butter and chocolate. Because they are no-bake, they’re quick to prepare and ideal for warm weather or last-minute entertaining.
Why you’ll love them
- Quick and fuss-free. With just five ingredients and a single saucepan, you can have these bars ready in minutes.
- No-bake. No oven required, so they’re perfect for hot days or when you don’t want to heat the kitchen.
- Family-friendly. Kids love making and eating them, and adults appreciate the sweet-and-salty, crispy-and-chewy contrast.
- Handy snack. Easy to pack for school lunches, picnics, parties or hikes.
- Budget-friendly. Uses simple, affordable pantry staples.
- Great to share. Package them up for friends, neighbours or coworkers—most people are delighted by a homemade treat.
About the ingredients
Butter: Adds richness and helps create the sticky binder for the bars. Salted or unsalted butter both work; salted butter lends a pleasant depth of flavor.
Peanut butter: Any peanut butter will work. Natural crunchy peanut butter gives a little extra texture, but smooth peanut butter is fine too. You can substitute other nut butters (almond, cashew) or seed butters (sunflower) for nut-free variations.
Marshmallows: Small or medium-sized marshmallows melt quickly and create the soft, chewy “caramel” that binds the cornflakes. A mixed pink-and-white bag gives a slight tint but won’t affect taste; white marshmallows are equally suitable.
Cornflakes: Use a basic box of cornflake cereal or a similar crunchy cereal you have on hand. The recipe is forgiving—different cereals will produce slightly different textures but still taste great.
Chocolate: Dark chocolate balances the sweetness nicely, but milk chocolate is an acceptable alternative. Use chopped chocolate or chips and melt gently for a glossy finish.
How to make peanut butter cornflake bars
First, line a square or rectangular baking pan with baking paper so you can remove the bars easily once set.
In a large saucepan, combine the butter, peanut butter and marshmallows. Melt them slowly over low heat, stirring occasionally, until the mixture is smooth and evenly combined. Keep the heat low to avoid browning or overcooking the marshmallows—the mixture should be glossy and pourable.
Once smooth, remove the pan from the heat and quickly fold in the cornflakes until each flake is well-coated with the sticky peanut butter-marshmallow mixture. Work quickly before the mixture cools and becomes harder to handle.
Tip the coated cornflake mixture into the prepared pan and press it evenly into the pan using slightly damp hands or a spatula. Aim for a compact, level layer so the bars hold together well.
Melt the chocolate gently—either in the microwave in short 20–30 second bursts, stirring between each burst, or in a heatproof bowl set over a pan of simmering water. Pour or spread the melted chocolate evenly over the top of the cornflake layer, smoothing it to the edges so it fills the gaps and creates a continuous top layer.
For a clean finish, score or cut the bars into squares while the chocolate is still soft. Cover the pan with plastic wrap and chill in the refrigerator until the chocolate is fully set, about an hour. Once firm, separate the bars and store them in an airtight container in the fridge for up to a week, or freeze for longer storage.
Helen’s top tips
- Work quickly once you add cornflakes so the mixture doesn’t cool and become difficult to mix and press.
- Spread chocolate to the edges. It will seep into the gaps and set into a neat, thin top layer—there’s no need to overdo the amount.
- Cut before chilling. Slicing while the chocolate is still soft prevents cracking and gives neater pieces.
Variations
These bars are delicious as written, but you can personalize them in many ways:
- Add nuts. Fold in about ½ cup of chopped or whole peanuts or your preferred nut for extra crunch.
- Swap the nut butter. Use almond butter, cashew butter or a seed butter like sunflower butter for a different flavor or a nut-free option.
- Add coconut. Stir in ¼ cup desiccated coconut and sprinkle a little on top of the chocolate before it sets.
- Mix in dried fruit. Add dried cranberries, raisins or chopped apricots; white chocolate on top pairs well with dried fruit.
- Use another cereal. Rice Krispies, Cheerios or Special K will all work if you don’t have cornflakes.
- Top with candy. For an extra-decadent version, stir chopped candy bars or peanut-butter cups into the mix or scatter them over the chocolate while it’s wet.
Recipe FAQs
Not always. Corn itself is gluten-free, but many commercial cornflake products include malt extract or other ingredients that contain gluten. Look for products specifically labeled gluten-free if you need to avoid gluten.
Stored in an airtight container, the bars keep well in the refrigerator for up to a week. Cornflakes may soften slightly over time. For longer storage, freeze the bars in freezer-safe bags or containers for up to three months.
5-Ingredient Peanut Butter Cornflake Bars
Ingredients
- 2 ounces (about 3 tablespoons) butter
- ½ cup peanut butter
- 10 ounces marshmallows
- 6 cups cornflakes (about 6 ounces; use 5 cups if using UK/Australian cups)
- 7 ounces chocolate (milk or dark)
Instructions
- Line a 9 x 13 inch pan (or similar) with baking paper.
- Melt the butter, peanut butter and marshmallows together slowly over low heat, stirring until smooth and combined.
- Remove from the heat and fold in the cornflakes until evenly coated.
- Press the mixture into the prepared pan using slightly damp hands or a spatula to prevent sticking, creating an even layer.
- Melt the chocolate gently (microwave in short bursts or use a double boiler) and spread it evenly over the cornflake layer, smoothing to the edges.
- Score or cut into 20–30 bars while the chocolate is still soft. Cover with plastic wrap and chill in the refrigerator until the chocolate has set, about 1 hour.
- Store in an airtight container in the fridge for up to a week, or freeze for up to 3 months.
Notes
Measuring cornflakes: If you use UK/Australian cup measures, reduce to about 5 cups (approximately 150 g). The recipe is forgiving, so slight variations won’t ruin the result.
Keep the heat low: Melting the butter, peanut butter and marshmallows slowly prevents the mixture from browning or becoming overly chewy.
Storage and freezing: Refrigerated bars stay enjoyable for up to a week; freeze portions in suitable containers or bags for longer storage.
Allergy swaps: Use sunflower or other seed butters for nut-free versions, or substitute your favorite nut butter as needed.