Butter or spray a 9x13 inch dish with non-stick spray. Stir the caramel topping into the marshmallow creme. Set aside.
Place cereal in a large bowl.
In a medium saucepan, melt the butter over medium-low heat. As the butter melts, it'll start to foam, then turn a clear golden color. Continue to stir the butter, scraping up any browned specks from the bottom of the pan as it starts to brown. It should have a nutty aroma.
Once browned and nutty, add the caramels, sweetened condensed milk and salt. Continue stirring until the caramels have melted and mixture is smooth. Turn heat down to low, add the marshmallows (reserving 1 cup), and stir until almost all of the marshmallows have melted.
Once melted, take the pan off the heat, add the reserved cup of marshmallows to the mixture, then immediately pour into the bowl of cereal. Stir until evenly coated.
Press half of the rice krispies mixture into the prepared pan. Pour the caramel-marshmallow creme mixture over the rice krispies and spread evenly. Pour the last half of the rice krispies mixture on top of the marshmallow creme and press into an even layer.
Allow to sit at room temperature for at least two hours before cutting into squares. If you can't wait that long, you can always pop the pan in the refrigerator for an hour instead.