Make the brownies according to the directions on the box. Sometimes, I add 1/2 c. chocolate chips to the brownies, but you don't have to.
Let the brownies cool.
Cookie dough layer:
Combine all the ingredients together and mix until well incorporated.
Spread the cookie dough on top of the cooled brownies.
Put the chocolate chips and the oil in a microwave-safe bowl and stir them.
Heat them in the microwave on high in 30-second increments, stirring after every increment until the chocolate chips are melted and smooth. Usually it takes around 1 1/2 minutes total.
Spread the melted chocolate chips over the cookie dough layer. Add candy if you wish.
Put in refrigerator to set.
We store the brownies in the fridge. You can take them out of the fridge 30 minutes before you serve them so they are room temperature. Landen wanted whip cream for the top of them so that is what we had for this birthday, but you could also serve them with ice cream. To be honest, they don't need either. :-)