Cream the butter and sugars. In a large mixing bowl, add the softened butter, granulated sugar, and brown sugar. Cream them together with an electric hand mixer, about 2-3 minutes.
Add the egg and vanilla. Now add the egg, egg yolk, and vanilla extract, and mix at high speed for about a minute.
Sift in the dry ingredients. Place a a fine-mesh sieve over the mixing bowl and add the all-purpose flour, baking soda, and salt. Sift the dry ingredients in and then mix at low speed with the hand mixer
Add in the rest of the ingredients. Finally, add the chocolate chips, chopped Hershey’s bars, mini marshmallows, and crushed graham crackers.
Mix and scoop. Mix everything together with a spatula and then scoop the cookie dough out with a medium-sized cookie scoop.
Bake. Place the cookie dough balls on a parchment paper-lined baking sheet and bake at 350 degrees Fahrenheit for about 9 minutes. Allow to cool.