Melt the butter in large pot over medium heat until melted. Reduce heat to low.
Add the marshmallows, reserving 1 cup, along with the salt. Stir until the marshmallows are almost completely melted. Stir in the vanilla extract and continue stirring until smooth.
Turn off the heat. Stir in the crushed Golden Grahams, rice cereal and remaining 1 cup of marshmallows. Stir until the cereals are evenly coated.
Transfer the mixture to a lightly greased or lined 9×13-inch pan and gently press into an even layer. Let cool completely before cutting.
Notes
Coarsely Crushed Golden Grahams: Place the cereal in a Ziploc bag and use a rolling pin or the back of a measuring cup to coarsely crush it. You want a mix of larger pieces and smaller crumbs.Brown Butter: Optional, but adds flavor. To brown butter, cook the butter until fragrant and small brown specks appear, watching closely because it can quickly go from browned to burnt.