Set the broiler to high heat and place the oven rack about 6 inches below the heating elements. Arrange the marshmallows on a sheet pan in a single even layer, so that no marshmallows are overlapping. Set aside until ready to use.

Heat the butter in a large stockpot over medium high heat until it has melted and begins to foam, stirring frequently to ensure that the butter cooks evenly. Keep a close eye on the butter as it continues to cook, stirring frequently, until the butter starts to turn golden brown and smells toasty. Once the butter reaches this stage, immediately remove the pan from the heat and pour the butter into a heatproof dish momentarily, so that the cooking process will be halted. Set aside while you toast the marshmallows.

Once the butter is ready to go, place the pan of marshmallows in the oven and broil for 30 to 60 seconds, until the marshmallows are puffy and deeply golden on top. (They cook quickly, so keep a very close eye on them!) Remove the pan from the oven.

Moving quickly throughout this step, pour the browned butter back into the stockpot, along with the bourbon and salt, and briefly stir to combine. Immediately transfer the toasted marshmallows to the stockpot (I find it’s easiest to do this with a large spatula) and briefly stir to combine. Add in the Rice Krispies and stir until they are more or less evenly coated. It’s ok if there are some marshmallow clumps in there.

Transfer the mixture to a parchment-lined (or greased) 9 x 9-inch baking dish, and gently press the mixture down into an even layer. Let the rice crispy treats cool until they reach room temperature.

Then slice, serve and enjoy!