Add the butter to a stock pot or Dutch oven over medium to medium-high heat. Stir continuously and remove from heat immediately when the butter reaches a light-milk-chocolate-brown color (when the butter starts browning, it will go quickly).

Stir in the can of sweetened condensed milk. Add in the entire bag of regular-sized marshmallows, and stir until the marshmallows melt completely. (If there isn’t enough residual heat in your pot to accomplish this, place it back over medium heat, stirring continuously until the mixture is melted, and then remove it from heat to finish up.)

Stir in the sugar cookie mix, and then add in the Rice Krispies, stirring to coat the cereal in the marshmallow mixture.

Finally, fold in the mini marshmallows, and then press the mixture into a nine-by-13-inch pan.

Let the treats cool, slice and serve. Store the treats in an airtight container.