Preheat oven to 350 degrees and line a large baking sheet with parchment paper.
Place room temperature butter into a stand mixer (or large bowl) along with the brown and granulated sugar. Beat to combine then add large egg and vanilla extract.
Add your dry ingredients next: All purpose flour, pudding mix, baking soda, corn starch, salt and white chocolate chips. Mix on low until just combined.
Fold in lucky charm's cereal
Place some additional white chocolate chips and lucky charms cereal on a plate.
Use a cookie scoop or ice cream scoop to scoop out the cookie balls
Grab your cookie dough ball and press it into the plate filled with white chocolate chips. Be sure to press all those chocolate chips and pieces of extra lucky charms marshmallows into the top and sides of the cookie.
Be sure not to press any chips/cereal onto the bottom of the cookie
Place the cookies on a parchment lined cookie sheet and place them in the freezer for 15 minutes to chill.
Once ready to bake, place the cookies on a parchment lined cookie sheet and space them atleast 2 and a half inches apart.
Bake them for 13-15 minutes, carefully transfer them to a cooling rack once they come out of the oven. Allow the cookies to cool and enjoy.