Grease your casserole dish with PAM cooking spray.
Over medium heat, brown the butter in a large saucepan or Dutch oven.
Add the vanilla, salt, and bag of jumbo marshmallows into the browned butter and stir. Continue to stir until the marshmallows are almost completely melted, with a few lumps remaining.
Remove the pot from heat; pour the cereal in one cup at a time and fold it into the melted marshmallow mixture. Add extra Rice Krispies and Golden Grahams until you reach your desired consistency.
Transfer your mixture to a casserole dish.
Grease your fingers or a spatula with PAM spray and gentely pat the mixture in to an even layer in the casserole dish.
Let the treats set for at least 1 hour at room temperature, or until firm.
Cut into squares and serve!