Prepare the cookie dough balls by beating together the butter, sugars, milk, vanilla, and salt until creamy.
Add in the flour and beat until well mixed. (Consuming raw or uncooked flour may pose a food safety risk, so proceed at your own caution.)
Stir in the miniature chocolate chips.
Roll into tablespoon full balls, place in a plastic container, and freeze until completely solid (overnight is best).
Once the cookie dough is frozen solid, prepare the cupcake batter by beating the cake mix, oil, water, and eggs until smooth.
Fill 24 cupcake tins lined with paper liners two thirds full with batter.
Place a frozen cookie dough ball in the center of each cupcake on top of the batter.
Bake at 350 degrees for 20-23 minutes or until tops are golden.
Remove and cool completely. For the frosting, beat together the butter, brown sugar, salt, milk, and vanilla.
Add in the powdered sugar gradually, scraping down the sides halfway through.
Add an additional 1/2-1 tablespoon milk if needed.
Pipe frosting on cooled cupcakes and sprinkle with additional mini chocolate chips if desired. Store in the refrigerator.