To make the cupcakes, prepare as directed on the cake mix box. I substituted 1/2 cup of applesauce for the oil. Stir in chocolate chips. Bake as directed on the box mix...until lightly golden. Allow to cool completely.
To make the cookie dough filling, combine the butter and sugar in a mixing bowl and cream together until light and fluffy, about 2 minutes.
Slowly beat in the flour, sweetened condensed milk, and vanilla and combined until dough-like.
Stir in the mini chocolate chips by hand. Cover and refrigerate until the mixture is firm, about an hour.
To fill the cupcakes, scoop out a small section from the center of each cupcake.
I used a TBSP measuring spoon that seem to take out just the right amount.
Fill each hole with a chunk of the chilled cookie dough mixture.
To make the frosting, cream together butter and sugar. Add vanilla and 2-3 tbsp. milk. Beat until frosting is light and fluffy.
Use leftover cookie dough to make mini cookie dough balls for decoration. You will have a ton of leftovers for that. Frost the filled cupcakes, and decorate with mini chocolate chips and mini cookie dough balls. YUM!