To make microwave Rice Krispies treats, gather 3 tablespoons of butter, 1 package of marshmallows and 6 cups of Kellogg's Rice Krispies brand cereal. Heat the marshmallows and the butter together in a microwave-safe bowl for approximately 3 minutes or until completely melted. Fold the cereal into the mixture in the bowl, transfer the contents to a greased baking pan, and allow everything to cool.
Rice Krispies suggests using either a 10-ounce package of regular size marshmallows, or 4 cups of miniature marshmallows. While three minutes cooking time in the microwave is a general recommendation, the time may vary depending on the make and model of the microwave. In any case, stir the marshmallow and butter mixture after the first two minutes, and then continue cooking it until creamy.
Avoid using stale marshmallows, as this compromises the end result. If necessary, fresh marshmallows can be replaced with a single 7-ounce jar of marshmallow crème product, but avoid substituting any low fat or margarine product for the butter. To properly spread the finished batter in the pan, use either a spatula, or cover the surface evenly with wax paper. Keep the treats for two days in an airtight container, or freeze them for up to six weeks. The treats should cool for at least 15 minutes before serving.