In large bowl, melt butter. Stir in sugars and vanilla.
Add flour and salt, stirring well.
Stir in milk, add chocolate chips and stir again.
Chill at least 30 minutes in fridge.
Once brownies have completely cooled and cookies have chilled, scoop about 1 Tbsp of cookie dough mix and roll it into a ball. Press against clean surface (i.e. countertop) to flatten the bottom.
Scoop a Tablespoon of brownie mix out of the prepared brownies (If you have a round tablespoon this works very nicely, almost like a cookie cutter, but it is not necessary to achieve the desired shape. I usually avoid the edges for a very moist, mold-able piece of brownie) and press onto cookie dough ball. Roll in your hands to create round shape. Set on parchment paper while you prepare all brownie/cookie dough truffles.
Once the inside of the truffles have been prepared, prepare chocolate coating by heating dark chocolate chips in microwave-safe bowl for 30 seconds and then stirring at 15 second increments until completely melted.
Dip truffles into chocolate (I set them on a spoon and used another spoon to pour chocolate over them) and then transfer to cookie sheet lined with parchment paper or wax paper. Sprinkle with mini chocolate chips.
Once all truffles have been coated move to refrigerator and allow to chill for at least 30 minutes before serving.