Spray a 9?13 baking pan with non-stick spray and line it with parchment paper. Set aside.

In a large pot over low heat, melt the butter and stir in the salt.

Once the butter has melted, add in the marshmallows and stir constantly until melted and mostly smooth. Small lumps are ok.

Remove the pot from the heat and gently fold in the cereal until evenly coated.

Gently spread the mixture into the prepared baking dish in an even layer. Don't pack it in or you'll end up with hard treats.

Optional: Immediately top with additional Lucky Charms marshmallows and sprinkles.

Allow to cool completely at room temperature for 30-60 minutes before slicing into bars.