Ingredients
Method
Prep Your Pan
- Grease a 9x13-inch baking pan generously with butter or nonstick spray, making sure to coat the sides. Set the pan aside and have it within arm's reach before you start cooking, because once the marshmallow mixture is ready, you'll need to move quickly.
Melt the Butter Low and Slow
- In a large, heavy-bottomed saucepan, melt the butter over medium-low heat. Do not rush this with high heat. As the butter melts, it will start to foam slightly. This is your cue to add the marshmallows.
Melt the Marshmallows
- Add the marshmallows to the melted butter and stir continuously with a wooden spoon or silicone spatula until they completely melt into a silky, smooth mixture with no lumps. Remove the pan from the heat immediately once fully smooth.
Fold in the Cereal
- Working quickly, pour in all 6 cups of Rice Krispies cereal at once and fold them into the marshmallow mixture using your spatula until every puff is coated. Fold gently rather than stirring aggressively to avoid crushing the cereal and losing the signature crunch.
Press Into the Pan and Cool
- Transfer the mixture into the prepared pan. Use a piece of buttered parchment or the back of a buttered spatula to press the mixture down evenly with a gentle, even press — do not press too hard or you'll compact the bars into dense hockey pucks.
- Let the bars cool at room temperature for at least 30 minutes before cutting into squares.
Notes
Total time is 15 minutes plus 30 minutes to set. Meal-prep tip: Make a double batch on Sunday, cut into squares, and wrap individually in plastic wrap for grab-and-go lunchbox snacks all week. Common mistakes to avoid: using high heat (scorches butter and marshmallows), over-pressing the bars (removes light airy chew), letting the mixture cool before pressing (it sets quickly), and cutting too soon (give full 30 minutes). Storage: Store cut bars in an airtight container at room temperature for up to 3 days with wax paper between layers. Freeze individually wrapped bars for up to 6 weeks; thaw at room temperature for 15 minutes before serving. Substitution tips: Use vegan butter and dairy-free marshmallows for a dairy-free version. Swap half the Rice Krispies for Cocoa Krispies or Fruity Pebbles for a fun twist. Store-brand cereal and marshmallows work just as well as name brands.