The original Rice Krispies Treat recipe is made by melting 3 tablespoons of butter with a package of marshmallows, and then combining the mixture with 6 cups of Rice Krispies cereal. This recipe makes 12 treats and takes about 30 minutes to prepare.
For best results, use stick butter rather than tub margarine and avoid reduced-calorie butters. Melt the butter over low heat and slowly stir in a 10-ounce bag of large marshmallows, 4 cups of miniature marshmallows or a 7-ounce jar of marshmallow cream. Stir continuously until the mixture is melted.
Remove the marshmallow-butter combination from the stovetop and stir in the Rice Krispies. Gently toss the cereal until the pieces are evenly coated. Spray a 13x9-inch baking pan with nonstick cooking spray, add the coated Rice Krispies mixture and press it into the pan using wax paper.
Allow the mixture to cool completely before cutting into squares and serving. Homemade Rice Krispies treats keep up to two days when stored at room temperature in an airtight container, but they taste best when served immediately.
To prepare the Rice Krispie Treats in a microwave oven, use the same ingredient amounts. Combine the butter and marshmallows into a microwave-safe bowl. Heat for two minutes, and stir. Heat for an additional minute if necessary to melt the marshmallows. Add 6 cups of Rice Krispies cereal to the bowl and stir to coat with marshmallows. Pour into the prepared pan, and allow to cool before cutting into bars.
The original recipe can also be frozen for as long as six weeks. Use wax paper to separate the Rice Krispies treats and freeze the treats in an airtight container.