In a large heavy pot or dutch oven, melt the butter over medium heat. Unlike normal rice krispie treats, you let the butter keep cooking until it becomes light brown. You have to watch it very carefully and stir frequently so that it doesn’t burn. As soon it becomes light brown turn off heat and add the marshmallows, stirring continuously. When marshmallows are melted completely move pot to counter and add cereal and salt, stirring until everything is equally distributed. Pour mixture into lightly greased 8-inch pan and it smooth out evenly in pan. I usually used waxed paper and my hands to do so because it gives me the most control. Let cool completely before cutting into squares.