Cream butter, sugar, and brown sugar together. Add milk and the vanilla, mix well.
Mix in the flour (see notes below) and salt until everything is combined. Fold in the chocolate chips.
Roll into tiny balls, place on a baking sheet and freeze.
Make Fudge
Line a 13x9 inch baking pan with parchment paper or grease well. Set aside.
Mix the sugar, butter and evaporated milk in a large saucepan. Heat over medium heat until it comes to a rolling boil, stirring constantly.
Boil for about 3 minutes, until 234º F. You can also test in a bowl of cold water. Place a small amount of the boiling mixture into the water, and use your fingers to try to shape it into a ball. Once it forms a soft ball that holds it shape it is done.
Remove from the heat. Add the chocolate chips and marshmallow cream, mix until well combined. Stir in the vanilla.
Quickly but gently stir in the frozen cookie dough pieces.
Spread mixture into your prepared pan. Let it set until it is cool before slicing.
Notes
To make the cookie dough 100% safe to eat you want to bake the flour for 5 minutes at 350º F, so it reaches a temperature of 160º F. Cool completely before making the dough.You can use approximately 1 1/2 cup of store bought edible cookie dough that you have rolled into balls and frozen in place of making your own.