Preheat the oven to 350 and prepare a cookie sheet with parchment. Set to the side.
Separate the marshmallows from the cereal and make the cereal flour. Place the cereal in a food processor and grind the cereal until it is like a fine powder.
In a medium-sized bowl, mix the cereal flour, all-purpose flour, baking powder, baking soda, and salt. Set to the side.
In a medium-sized bowl with a hand mixer or in the bowl of a stand mixer with a paddle attachment, cream the butter with the sugar until light and fluffy, about 2-3 minutes. Scrape down the sides of the bowl as needed and add in the eggs, followed by the vanilla.
Add the dry ingridents to the wet ingreident and mix until combined. Fold in the cereal marshmallows.
Scoop the cookie dough balls using a cookie scoop into about one tablespoon in size. Use the bake of the cookie dough scoop or your thumb to make a circular imprint in the cookies. Add the fluff to the indent and cover the fluff by pinching over the cookie dough. Top the cookie dough balls with extra marshmallows.
Bake the cookies in the oven for 9-11 minutes. When the edges of the cookies are slightly golden brown, take the cookies out of the oven. Let the cookies cool on the cookie sheet for 10 minutes before moving them to a cooling rack.
