Bake brownies according to box directions and let cool completely, overnight on the counter or four hours in the refrigerator. (Note: You can use your favorite homemade brownie recipe here, you just might need to adjust how much chocolate frosting you use.)
Beat together the powdered sugar, butter, mint extract, and green food coloring. Place the frosting in a piping bag.
Break up the brownies with the back of a spoon in a large bowl. Gradually add the frosting until you get the right consistency. You want it to be able to stick together in ball form, but not be too sticky.
Make one inch balls out of the brownie mixture, and then make a crater in the middle of it. Pipe in the mint frosting. Take an additional small piece of the brownie mixture and place it over the top, sealing in the mint frosting. Roll it into a smooth ball and set aside.
Once all the brownie bombs are formed, freeze them for 15 minutes. Transfer them from the freezer to the refrigerator.
Microwave 1 cup to begin with of the chocolate chips (melt the second cup once you've used up the first). Taking out two brownie bombs at a time, submerge them in the melted chocolate and take them out with a fork, tapping off the excess chocolate. Place on wax paper and allow to dry completely before storing in an airtight container in the refrigerator.