Keep the heat low under the butter and let the marshmallows go fully slack and glossy before the cereal goes anywhere near the pot. That low-and-slow melt is what keeps the batch chewy instead of hard, because marshmallow that scorches turns brittle once it sets. I stir in a pinch of salt and a little vanilla off the heat, which sounds fussy for a five-ingredient snack but cuts the one-note sweetness. Work fast once the Rice Krispies hit the pot, since the mixture stiffens as it cools.
The treat traces back to the 1930s at Kellogg's, where the recipe is usually credited to Mildred Day and Malitta Jensen, two staffers who reportedly worked it up for a Camp Fire Girls fundraiser. It spread through the cereal box itself, printed right on the package, which is why nearly everyone learned the same butter-marshmallow-cereal ratio.
Some recipes are timeless. This is one of them.
Butter. Marshmallows. Cereal. That’s it. 10 minutes. No oven. Sticky, gooey, crispy perfection. Make them with a kid. Eat them like a kid. No judgment.
Step-by-Step Instructions
11
Prep the Pan
Grease a 9×13 baking dish with butter or non-stick spray.
22
Melt the Butter and Marshmallows
In a large pot over low heat, melt butter.
Add marshmallows. Stir constantly until completely melted and smooth.
Remove from heat. Stir in vanilla and salt (if using).
33
Add the Cereal
Pour in Rice Krispies. Stir quickly until cereal is fully coated.
Don’t overmix (cereal gets crushed).
44
Press Into Pan
Transfer mixture to prepared dish.
Press firmly into an even layer using greased hands or wax paper (mixture is sticky!).
Store in an airtight container for up to 5 days. Do not refrigerate (they get hard).
Freezer Friendly:
Freeze for up to 6 weeks. Thaw at room temperature.
Pro Tip:
For extra gooey treats, add 1 extra cup of marshmallows. For extra crispy, add 1 less cup.
Swaps & Substitutions
Unsalted butter → salted works fine; just skip the extra pinch of salt at the end
Marshmallows → use 4 cups mini in place of the 10 oz bag; they melt faster and more evenly than the big ones
Dairy-free → swap in a vegan butter stick and vegan marshmallows (check the bag, since many contain gelatin)
Rice Krispies → any crisp rice cereal works; gluten-free crisp rice keeps the batch celiac-safe
Vanilla extract → optional, leave it out with no real loss, or trade for a little almond extract for a different note
Brown butter upgrade → cook the butter past melted until it smells nutty before adding marshmallows, for a deeper flavor
Questions & Answers
Why did mine turn out hard instead of chewy?
Usually too much heat or too many marshmallows melted too long. Keep the burner on low, pull the pot the second the marshmallows are smooth, and don't pack the mixture into the pan with much force.
Can I make these ahead?
Yes. They hold at room temperature in an airtight container for up to 5 days, and they freeze for about 6 weeks. Don't refrigerate them, since the fridge dries them out and stiffens the texture.
How firmly should I press the mixture into the pan?
Press just enough to make an even layer with no big gaps. Pack it down hard and the bars set dense and tough; a light, even press keeps them tender.
When do I add mix-ins like chocolate chips or M&Ms?
Fold them in after the cereal is coated and the pot is off the heat, working quickly. If the mixture is still very hot, chocolate chips will melt and streak, so let it cool a minute first or use them as a topping you press into the surface.
Do I need the vanilla and salt?
No, both are optional. The salt is the one I'd keep, since a pinch balances the sweetness; the vanilla is a small bonus you can skip without anyone noticing.
