First, preheat the oven to 350 degrees Fahrenheit. Line a baking sheet with parchment paper.

In a large mixing bowl or the bowl of a stand mixer, add the unsalted butter, sugar, and brown sugar. Beat until creamy and no clumps of butter remain.

Then, add in the egg, egg yolk, and vanilla. Beat until mixed.

Sift in the flour and baking soda. Stir until a cookie dough forms.

Then, add in the rice cereal, mini marshmallows, Oreos, corn flakes, chocolate chips, and granola. Stir together. The dough will be very thick.

Use an ice cream scoop to scoop out balls of dough. Use your hands to roll into tight balls. This is important to keep the cookies held together. Place at least 3 inches apart on the pan.

Bake for 9 to 11 minutes, until the edges are lightly golden brown.

Finally, remove from the oven. Cool on the pan for 10 minutes before carefully transferring to a cooling rack.