To make Rice Krispies treats, melt 3 tablespoons of butter in a saucepan over low heat, and stir in 10 ounces of marshmallows, stirring constantly. When the marshmallows are melted and smooth, gently stir in 6 cups of Rice Krispies cereal until the cereal pieces are evenly covered. Spread the mixture in a greased 13-inch by 9-inch pan, and press the mixture evenly in the pan with a greased spatula.
To make Rice Krispies treats in the microwave, put the 3 tablespoons of butter and 10 ounces of marshmallows together in a microwave-safe bowl. Turn the microwave on high for 2 minutes, and stir the marshmallows. Heat for an additional minute on high if necessary to melt the marshmallows completely. Stir in the cereal, and spread the mixture in the pan in the same way as in the stove-top directions.
Kellogg's recommends using fresh marshmallows for the best-tasting Rice Krispies treats. An alternative to melting marshmallows is using a 7-ounce jar of marshmallow creme. Real butter works better than low-calorie margarine.
Add other ingredients such as sprinkles, peanut butter, cookie pieces or candy chunks for flavor varieties. For a simple option, top the bars with rainbow sprinkles immediately after pressing the mixture into the pan. For individual servings, press scoops of the cereal mixture into greased cupcake pans, and top them with frosting. Another individual serving option is to cut the bars into squares and put them on sticks to make Rice Krispies treat pops. Dip the pops in melted chocolate.