In the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), cream the butter, granulated sugar, and brown sugar together.
¾ cups unsalted butter, ½ cup granulated sugar, ½ cup brown sugar
Add the eggs and vanilla extract and mix again until well combined. Set aside.
2 large eggs, 1 teaspoon pure vanilla extract
Add the Lucky Charms cereal to a food processor and grind into a fine flour.
1½ cups Lucky Charms cereal pieces
In a medium bowl, whisk the Lucky Charms, flour, baking soda, and salt together. Stir into the wet ingredients until just combined.
2 cups all-purpose flour, 1 teaspoon baking soda, ½ teaspoon kosher salt
Gently fold 1 cup of the lucky charms marshmallows and all of the baking chips into the cookie batter. Cover and refrigerate for 2 hours.
1 cup mint chocolate baking chips, 1½ cups Lucky Charms marshmallows
Preheat the oven to 350°F and line a large baking sheet with parchment paper.
Using a cookie scoop or your hands, form 1-inch balls from the batter and place 6-8 on the pan about 1 inch apart from each other.
Lightly press 3-4 leftover marshmallows into each of the cookies.
Bake for 6-8 minutes, or until the edges turn a light golden color and the tops don’t look wet anymore.
Remove the pan from the oven and let the cookies cool for 5 minutes before removing them from the pan and letting them cool completely on a wire rack.
Repeat the baking process with the remaining batter.