Nonstick cooking spray
4 tablespoons unsalted butter
One 10-ounce bag mini marshmallows
6 cups crispy rice cereal, such as Rice Krispies
1 teaspoon pure vanilla extract
Pinch kosher salt
Decorative toppings, optional (see Cook's Note)
To decorate these cereal treats for holidays and special occasions, sprinkle the top with 1/4 cup of your favorite sprinkles, chocolate chips and/or candy-coated chocolates (such as M&M’s) while still warm, pressing gently so they adhere.