Line a 9x13 inch pan with nonstick foil or parchment paper. Alternately, you can use regular foil and rub it generously with extra butter. Also have ready an extra sheet of nonstick foil or parchment.
Put the cereal in a large mixing bowl and set aside.Note: The original recipe instructs you to grease the bowl. I forgot to do this and didn't have any problems with sticking. It seems like a good idea, though.
In a large nonstick saucepan, melt the butter and maple syrup together, stirring constantly. Boil gently for two minutes over medium heat, stirring constantly. Reduce heat and boil for another 30 seconds.
Add the marshmallows and stir until melted, then pour mixture over the cereal and stir well.
Pour into the pan. Lay the extra nonstick foil sheet (or parchment or buttered foil) over the cereal mixture and press down firmly. Let cool completely.
Lift from pan and cut into squares or bars.
Adapted from Modern Maple (The Northern Plate) by Teresa Marrone (Author). Published by the Minnesota Historical Society