In a large saucepan, melt butter or margarine over low heat. Add marshmallows a cup at a time and stir until well blended.
Turn off heat when marshmallows are melted.
Add cereal slowly and stir with a buttered spoon or spatula to combine.
Place in a large (buttered) baking pan (cereal should be no more than 1" deep) and cool. Use a football shaped cookie cutter to cut out football shapes after the cereal mixture has cooled.
Meanwhile, melt 1 cup semisweet baking chips. I used the microwave on 50% power, 30 seconds at a time, until chips melt together.
Spread over each football and let cool until firm.