cut your butter into even slices. On med-low heat melt butter. Stirring continuously as it goes from light yellow, to golden to a med brown. When the butter starts to foam it will quickly turn from golden yellow to a tan. Turn off heat and immediately add marshmallows.
Stir in marshmallows in warm pan and toss with the hot butter. This will start to melt the marshmallows. When the mallows turn melty and starting to puff up add in half your Rice Krispies .
Stir together, add in remaining Rice Krispies. When just combined place in a parchment paper or non-stick 9x13 pan. Using the butter wrapper or buttery fingers press down on Rice Krispie treats to make them nice and firm.
Stir until everything is just combined. Do not over stir. If you noticed the butter is starting to separate you probably are stirring too much. Place in the 9x13 pan. As the treats cool the butter will re-incorporate into the treats.