Step 1

Preheat oven to 400 degrees. In a large mixing bowl, cream butter, brown sugar, and sugar for 4 minutes, until light and fluffy. Scrape the sides of the bowl halfway through.

Step 2

Add eggs and vanilla.

Step 3

Fold in flour, cornstarch, baking soda, and salt. Add milk chocolate chips. Reserving 1 cup of milk chocolate chunks to add after the cookies have been removed from the oven.

Step 4

Line a light-colored baking sheet with parchment paper or Silpat. Place cookie dough into large 4-ounce balls. Bake for 8-10 minutes. While baking, get marshmallow fluff, milk chocolate chunks, and graham crackers ready.

Step 5

Remove cookies from oven and immediately place a dollop of marshmallow cream in the center. Press chocolate chunks and bite-size graham crackers into the cookies.

Step 6

Let set up for about 10 minutes before eating.