How to Make It
Pulse cereal (without marshmallows) in a food processor until finely ground. Stir together flour, salt, baking soda, and ground cereal in a large bowl. Set aside.
Beat together butter, brown sugar, and granulated sugar with an electric mixer on medium speed until light and fluffy, about 5 minutes. With mixer on low speed, add eggs 1 at a time, beating until combined. Add vanilla.
With mixer running on low, gradually add flour mixture, beating until just combined. Fold in marshmallows with a rubber spatula. Chill 30 minutes or up to an hour. Preheat oven to 350°F. Line a baking sheet with parchment paper.
Scoop dough with a 1 to 1 1/2 tablespoon ice cream scoop. Dip each scoop into sprinkles, and place on prepared baking sheet, about 2 inches apart. Bake in preheated oven until light brown around edges, 8 to 12 minutes. Transfer to a wire rack to cool. Sprinkle with edible gold flakes, if desired. Enjoy!