Step 1

Preheat oven to 350F and line a baking sheet. Set aside.

Step 2

In the bowl of a mixer fitted with a paddle attachment, beat unsalted butter and granulated sugar together on medium speed until smooth, about 1 minute.

Step 3

Add in egg and vanilla. Mix until combined

Step 4

Using a food process or blender, blitz cereal until it becomes a powder. This will be your cereal 'flour.'

Step 5

In a medium bowl, whisk together all-purpose flour, cereal 'flour', baking powder, baking soda, and salt.

Step 6

Add the dry ingredients into the butter-sugar mixture. Mix on medium-low speed until just combined, about 45 seconds.

Step 7

Using a rubber spatula, fold in the cereal marshmallows and regular marshmallows until evenly distributed.

Step 8

Using an ice cream scoop, scoop out dough balls onto lined baking sheet.

Step 9

Optional: roll each dough ball in granulated sugar before baking.

Step 10

Bake for 11 - 14 minutes until edges are golden.

Step 11

Remove from oven and allow cookies to cool on baking sheet for 10 minutes before transferring to cooling rack to cool completely.